Penny + Giles, a business group of Curtiss-Wright Controls and designer and manufacturer of joystick controllers, solenoids and high precision sensing technology, is supplying its TPS280DP throttle position sensors to UH Racing, the University of Hertfordshire’s Formula Student racing team.
Used as a testing ground for the next generation of world-class engineers, Formula Student challenges university students from around the world to design and build single-seat racing cars with the aim of inspiring the next generation and addressing the all too apparent skills shortage in engineering.
Commenting for UH Racing’s Formula Student team, engine specialist Craig Brant says: “The 2011 season has been one of the toughest yet, but UH Racing was named top UK team and achieved an overall third place at the Formula Student UK event held at Silverstone. We were also awarded top UK team and overall seventh place at the Formula Student Germany event.”
Like many other racing formulas, vehicles entering the Formula Student event are subject to restrictions, including a maximum 600cc engine size and air restrictors to the engine. However, Formula Student is one of the most open formulas in the world with teams able to choose single cylinder or v-twin engines, many derived from powerful, high-revving motorbike units. UH Racing’s car – dubbed UH14 because it is the University’s fourteenth combustion-engine vehicle since entering the event in 1998 – uses a 600cc, four-cylinder, four-stroke Yamaha engine.
For 2011 many teams have taken a different approach, opting for a lightweight design with very small wheels and a single cylinder engine to give them an advantage on the skid pad and sprint course.
However, as Craig explains: “With UH14, UH Racing has continued the approach of using a more powerful but slightly heavier engine, but has also started to adopt Formula One technologies including the use of a carbon fibre body, tyre pressure monitoring systems and tyre temperature. We have also been lucky to have students in work placements with Cosworth Racing who, through sponsorship, have offered technical advice and supplied useful equipment.”
He goes onto say that because the track for the 2011 endurance event was tight and twisty, UH Racing wanted to replace its usual gear lever with a paddle shift system to enable drivers to change gears more quickly, easily and safely, and in turn improve lap times.
The initial student-designed system involved steering wheel mounted paddle switches actuating a solenoid attached to the engine block, which in turn moved a gear selector on the engine to change gear. However, tests revealed that the system’s ECU read the gear position based on the wheel speed of the car and the data couldn’t accurately provide drivers with a dashboard display showing which gear was selected.
To achieve a more definitive gear position the team decided to monitor the barrel of the engine using a sensor installed on the barrel position of the gearbox. Now, when it moves the selector forks to change gear, the rotation is changed and the team is able to determine exactly which gear has been selected.
UH Racing’s Yamaha-based engine has its gearbox mounted to the engine, making it a very compact unit. However, the sensors mounted on the engine block and gearbox barrel are subjected to extremely high levels of shock and vibration over long periods, so the team needed a sensor that would withstand the mechanical abuse from the engine/gearbox configuration.
Having already partnered Active Technologies (AT Power) in developing a Formula Student throttle body, the University of Hertfordshire again approached the company for advice. AT Power had themselves recently begun using Penny + Giles throttle position sensors on its own throttle bodies and after further testing and discussions with Penny + Giles engineers, the same advanced TPS280DP sensors were also specified for use on UH Racing’s gear position system.
As Craig explains: “Previously, we had used potentiometer-based sensors from another manufacturer, but we decided that for this season a more advanced sensor was needed. As AT Power had recommended the TPS280DP for the throttle bodies, we approached Penny + Giles to source the same sensors for our new gear position system.”
Penny + Giles tailored the throttle position sensor to UH Racing’s specifications and the team designed its own mounting bracket for the engine. The sensor was then factory-programmed with a 360° rotation to allow it to read the full range of gears. The throttle position sensors are now connected to the gear position barrel and provide feedback on the exact position of the barrel and therefore the exact gear number.
The Penny + Giles TPS280DP uses a factory programmable Hall effect sensor with two outputs that can be programmed individually for angular range, output range and direction. It has no contacting sensor parts, which ensures zero signal degradation over the lifetime of the sensor, and has a tested life of more than 60 million operations – more than 18 times the life of an equivalent potentiometer. In addition, when powered with 5Vdc, the sensor has an operating temperature range from -40 to +140ºC.
The TPS280DP has been specifically designed to work in harsh motorsport environments and has excellent shock and vibration resistance. Its drive and body are IP69K-rated to provide excellent protection against the ingress of dust and fluids. It is also mechanically interchangeable with many existing potentiometer-based throttle sensors using 32mm mounting centres, and is designed to interface with most common throttle body D type spindles.
“The new setup works very well.” says Craig. “Instead of the ECU trying to calculate the gear position, the TPS280DP now provides us with an exact position, ensuring that the correct gear is displayed on the dashboard. In endurance events this helps the driver to prepare the car for the course ahead while navigating the tight and twisting courses.”
The updated throttle bodies and new gear position system have been thoroughly tested on and off the track, on cars from both the 2010 and 2011 seasons, and have proved very reliable.
Summing up the Penny + Giles contribution Craig Brant says that while the team’s engines aren’t too highly stressed they are run very hard and adds: “We expected the sensor to last the life of the engine and therefore the season, and we haven’t been disappointed.”
With a legacy spanning more than 50 years, Penny + Giles is a recognised leader in the design and manufacture of joystick controllers, sensors and industrial solenoids. It has extensive experience in providing solutions for monitoring and control under extreme operating conditions.
Contactless Rotary Position Sensors
The company’s extensive range of rotary position sensors offer angle measurements from 10° to 360° and use Hall effect, inductive or potentiometric technologies, all packaged in compact or rugged housings, with environmental protections to IP68 and IP69K. Its dual-output, contactless range has been specially developed to meet the operating requirements of many industrial position sensing applications in the general engineering, automation and process control sectors.
Designed with 21st century applications in mind, Penny + Giles contactless rotary position sensors use the latest advances in 12bit Hall effect sensing technology and are factory-programmed to provide OEM’s with a variety of previously unavailable options. These include single- or dual-redundant outputs, clockwise or anticlockwise rotation and measurement angles from 0-20° to 0-360° in 1° increments.
Most models can withstand operating temperatures between -40°C and +140°C (+170°C for 72 hours for NRH/TPS models); are tested to resist severe shock and vibration; and have an EMC immunity of 100V/m.
The sensors are designed to operate from a 5Vdc regulated or 9 - 30Vdc supply; and outputs can be PWM or analog voltage (nominal 0.5 - 4.5Vdc) over the measurement range, with clockwise or anticlockwise shaft rotation. A choice of 341 different electrical angles from 20° to 360° are possible and 12bit resolution (0.025%) is available over the selected measuring range with a non-linearity better than ±0.4% and temperature stability better than ±50ppm/°C. The sensor’s analog output option has a very low output noise level of less than 1mV rms.
Contactless Tilt Sensors
The company’s STT tilt sensor range uses solid-state 3D-MEMS technology to measure the sensor's inclination relative to earth's gravity. By using solid-state system-on-chip technology, the STT series provides distinct advantages in reliability, stability and compactness over fluid-based, electrolytic and pendulum operated sensors. For maximum flexibility this new range has a low power requirement of less than 6.5mA, so it can be used in hard-wired or battery-powered wireless systems.
The IP68-rated STT280 is supplied in a compact 28mm diameter corrosion-resistant body with crush proof inserts in the mounting flange. The larger STT500 is supplied in a rugged, marine grade cast aluminium housing with a protection rating of IP69K.
Both sensors can withstand operating temperatures from -40°C to +125°C and have been tested to withstand a 3m drop onto concrete (maximum 20,000g). They are available with a choice of measurement ranges from ±10°, ±20°, ±30° and ±60° and can operate from a 5Vdc regulated or 8 – 30Vdc unregulated power supply.
Contactless Linear Position Sensors
Penny + Giles’ comprehensive range of linear position sensors use non-contacting technologies and cover measurement ranges from 10 to 5000mm. A choice of models and mounting configurations, including embedded in-cylinder linear transducers, suit a wide range of hostile industrial applications.
The company’s SLT190 is designed to provide reliable, fit-and-forget position sensing (up to 500mm) within a compact transducer size for the most arduous operating environments. It can withstand operating temperatures from -40 to +150°C, has been tested to withstand shocks to 10,000g and, with EMC Immunity of 100V/m, the SLT190 is suitable for the harshest of applications.
To minimise size and the impact on the overall system, separate signal conditioning electronics (EICT or EICTM) are housed in rugged IP66 or IP68 rated enclosures. The electronics module can be located up to 10m from the transducer, away from any hostile conditions (vibration, mechanical impact, temperature) that the position transducer may encounter during operation. The result is a more reliable transducer solution, easily installed and adjusted and more flexible in the choice of outputs - including voltage, current and digital PWM.
The Penny + Giles SLH100 has been specifically designed to provide precision, cost-effective position sensing using the contactless Hall effect principle, with the sensing system comprises only two parts: the sensor and the magnetic activator. As a fully encapsulated electronic device it is intended to compete with sealed potentiometers and inductive sensors.
This robust, maintenance-free and easy-to-fit sensor can be used for a variety of control applications and its durable design and absence of mechanical linkages makes this sensor attractive for use in harsh environments - where particles, moisture, temperature and vibration can be present.
Sensors In Action
For a recent application, Penny + Giles is supplying its STT280 tilt sensors and SRH280DP rotary Hall effect sensors to Sarclad Ltd to provide critical measurements for an In-Chain Strand Condition Monitor – a precision, online measurement system used to monitor continuous casting machine rolls used in the steel making process.
The In-Chain Strand Condition Monitor (In-Chain SCM) is permanently installed in the steelmaking process to enable automatic fixed-roll alignment and roll-gap measurements to be performed at the beginning of every casting, without affecting production activities. The Penny + Giles sensors were specified to meet the stringent requirements of a system that is robustly engineered to endure the extremely hostile casting environment.
Commenting for Sarclad, In-Chain SCM manager Richard Cowlishaw says: “With a continuous cast system able to produce in excess of $1million worth of steel a day time is of the essence, so interrupting production to measure the condition of the casting machine could cost steelmakers huge amounts of money. Installing a Sarclad In-Chain SCM system ensures that measurements are taken automatically at the start of every cast, so that costly downtime is avoided and quality of product is maintained.”
The Penny + Giles STT280 tilt sensors are fitted to the In-Chain SCM to measure the fixed-roll alignment of the casting machine using spring-loaded blades that tangent pairs of rolls to measure the angles between them. The data is then processed to identify rolls and segments that are out of position relative to other rolls within each segment.
Sarclad had previously used inclinometers, but specified the Penny + Giles tilt sensor because its compact size and extremely robust construction proved more effective and robust for the application. In addition, because measurements are taken while the continuous cast system is moving, inclinometers were prone to resonate or create a spike output. In contrast, the STT280 tilt sensor features 3D-MEMS technology, which provides a naturally-damped response that is unaffected by knocking or vibration. This feature is especially important for continuous steelmaking operations where accurate measurements are vital, as Richard Cowlishaw explains.
“The steel making process involves pouring molten steel into a caster mould and oscillating the mould to prevent the liquid steel sticking to the sides while it solidifies. The vibrations from the action of the oscillator affects the measurements taken with traditional inclinometers, by producing spiked rather than smooth outputs, which corrupts the measured data.
The caster operates from ninety degrees vertical to zero degrees horizontal, so in order to accurately measure between the two angles it is necessary to measure beyond them. Penny + Giles were able to customise the STT280 sensor to measure between 92 degrees and -2 degrees, providing the calibration points we needed outside the measuring range.”
He goes onto say that Sarclad was so impressed with the Penny + Giles sensors that they have also been installed on its traditional Strand Condition Monitor, which is the offline equivalent of the online In-Chain system.
Sarclad also uses Penny + Giles SRH280DP rotary Hall effect sensors to measure gap displacement on the In-Chain SCM system, replacing the rotary inductive position sensor (RIPS) used in the original design.
Says Richard: “The RIPS were too big, were influenced by forces exerted on the shaft and used a technology that proved to be unsuitable for the application. Axial loads on the RIPS shaft also caused the output to fluctuate even though it wasn’t being rotated.” He adds that potentiometers also proved problematic because the application only needed a small length of track, which meant that the conductive grease degraded prematurely, causing spikes in the signal.
When Penny + Giles introduced the SRH280 rotary Hall effect sensor to provide uniform feedback, Sarclad immediately realised its benefits even though it was only initially launched as a single channel sensor. However, the range was programmable, which allowed the company to get the maximum resolution from the 30 degrees rotation output they required. Sarclad now fits the recently developed Penny + Giles SRH280DP two channel version, which can be configured with both channel outputs increasing with clockwise or anti-clockwise shaft rotation, or one clockwise with one anti-clockwise.
“Being a non-contact Hall effect sensor, any pressure applied to the shaft in an axial direction does not affect the output.” says Richard. “It is also available as a regulated or unregulated version, is very stable and not affected by heat or shock, which is a real bonus for this particular application.”
The SRH280DP is fitted as part of a gap transducer, which has a spring-loaded rotary arm that extends out to contact the caster rolls to provide an absolute measurement for the distance between the pair of opposing rolls.
New levels of sophistication
The latest developments in sensing and control system technology are bringing a whole new level of sophistication to monitoring and control, resulting in much more efficient operation. Highly reliable signals from the latest sensor developments, combined with intuitive control system software, mean that process control equipment can be tuned to optimise performance to individual applications. At the touch of a few buttons, routine operations can be performed throughout the process to deliver considerably better productivity.
Involving component suppliers such as Penny + Giles at the earliest possible stages of development often produces the most cost-effective solution in the shortest possible development time. This is achieved by combining Penny + Giles’ vast experience of the type and layout of equipment controls with the more subjective input of OEM engineering and marketing departments.
Penny + Giles, a business group of Curtiss-Wright Controls and designer and manufacturer of high precision sensing technology, is helping gearbox specialist Geartronics to significantly improve the shift times and reliability of its motorsport paddleshift system using Penny + Giles SRH280DP Hall effect rotary sensors.
Commenting on the change to Penny + Giles Hall effect sensor technology, Geartronics managing director Neil Wallace explains: “The strategy to successfully get out of one gear and engage the next as quickly as possible is not just a case of cutting the engine or blipping the throttle for a few milliseconds and hoping for the best!”
Gear up-shifts or down-shifts are essentially a two-stage process - first to disengage the current gear, then to engage the next gear. The times for both processes vary depending on complex dynamic factors acting on the vehicle at the time, which are impossible to model or predict.
The Geartronics 'closed-loop' control system uses a gearbox control unit (GCU) in conjunction with Penny + Giles SRH280DP sensor inputs to modify its own operation - in real-time. In the context of semi-automatic gear selection, the closed-loop system monitors the gear position sensor to determine the precise angular position of the gearbox selector barrel. This information is fed back to the GCU control algorithm so the pneumatic actuator, engine torque reduction or throttle blip can be turned on and off as necessary to effect the fastest and most reliable gear shifts.
Neil emphasises that a closed-loop system is absolutely reliant on receiving accurate feedback from the sensor, so the Penny + Giles SRH280DP Hall effect sensor is effectively the cornerstone of the system.
By contrast, an 'open-loop' system has no feedback mechanism, and simply relies on fixed timers to govern the various shift events. An open-loop system therefore applies the same engine cut or throttle blip duration for every shift, regardless of whether those times are appropriate for each individual shift requirement.
Geartronics’ sequential gearbox shift systems are used in extreme autosport environments such as formula and GT car racing and rallying, and, more recently, have been specified on the Ariel Atom V8 road car. Combining sophisticated electronic control and extremely accurate Penny + Giles rotary sensors, the pneumatic shifter mechanism directly controls the gearbox cam-drum or barrel, and eliminates the requirement for driver operated shift linkages.
A committed user of Penny + Giles SRS280 resistive rotary position sensors for more than nine years, Geartronics began specifying a competitor’s sensors following the introduction of Hall effect technology, but as Neil Wallace explains, they very quickly proved unreliable, were causing numerous problems, and in some applications, were failing within a couple of hours due to the high levels of vibration generated by V8 race engines.
“Fortunately, at around the same time we learned that Penny + Giles had introduced its own hall-effect sensor, the SRH280DP, so we began testing them on our shifter systems and saw an immediate improvement. In fact, when they were installed mid-season on two single-seat V8 racing cars, they proved 100% reliable for the remainder of the season.”
He says that the non-contact technology used in Penny + Giles Hall effect sensors is more reliable as it’s not affected by vibration – an important benefit compared to the wear experienced with resistive contacts, and adds that direct comparison is difficult as Geartronics hasn’t had a Penny + Giles SRH280DP fail.
Penny + Giles provides Geartronics with a mix of standard and bespoke SRH280 sensors including the special, double-output SRH DP versions that can be used to send separate signals to both the GCU and the engine management system (ECU) or data acquisition systems.
Summing up Neil Wallace says that for any semi-automatic shift system to work consistently and reliably under all conditions, the GCU needs, ‘as an absolute minimum’, to measure the gearbox barrel position, throttle position and engine speed, and that’s exactly what the Penny + Giles SRH280DP Hall effect sensors help us to do.
Geartronics provides its sequential gearbox shift systems to winners in a wide range of motorsport disciplines such as British and European Hillclimb Championships, open-wheel ‘formula’ racing, GT & sportscar endurance racing and rallying.
For enthusiasts requiring more information, a YouTube video (Search: Steiner Marcel La Roche 2011) shows an under bonnet view of a system operating real time in a Steiner Motosport Osella FA30.
Penny + Giles’ popular SRH280 contactless rotary position sensors use a factory programmable non-contact Hall effect sensor system. The SRH280P & SRH280DP provide reliable and accurate rotary position measurement in extreme motorsport and industrial environments where shock and vibration can occur. These sensors use the popular 38mm flanged housing with an environmental protection rating to IP68.
SRH280P & SRH280DP operate from either 5Vdc regulated or 9-30Vdc unregulated power supply and are available with analog (0.5 - 4.5Vdc and 0.1 - 4.9Vdc) or digital (PWM) output signals.
The sensor is factory programmable, allowing you to specify the output signal type, the measurement range (0-20° to 0-360° in 1° increments) and the output direction (clockwise or anticlockwise). It has a 12 bit resolution (0.025%) over the selected measuring range, and operates from -40 to +140°C when powered at 5Vdc.
Key Features include contactless Hall effect technology; single or dual output channels; 5Vdc or 9-30Vdc supply; total sensor measurement range from 0-20° to 0-360°; analog or digital (PWM) output; 12 bit resolution over selected measuring range; low noise level (1mVrms) on output signal; operating temperature -40° to +140°C; environmental protection to IP68; crush-proof mounting flange with steel inserts, and rapid availability.
