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Penny + Giles, a business group of Curtiss-Wright Controls and designer and manufacturer of high precision sensing technology, is supplying its contactless rotary position sensors and advanced joystick controllers to help control the latest Transtacker trailer from Big Bale Company South. The versatile, multi-function trailer, which sells in the UK and around the world, has recently benefited from a major upgrade of its control system and now features highly sophisticated electronics developed by control specialist Tedd Engineering.
Explaining the significance of the new control system Paul Bowles of Big Bale Company South says the control system is predominantly responsible for controlling and managing the Transtacker's hydraulics. "The hydraulics perform the three principle functions of the Transtacker trailer, which are to pick up, lift and rotate bales from ground level to the machine's trailer. This involves controlling the operation of large double tines and a turntable, which travel between zero and 180 degrees."
He goes onto say that in the company's experience, agricultural equipment is plagued with poor sensors so they were determined that sensors for the new control system would be tailored to do exactly what they wanted and would future-proof the functionality.
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Big Bale South's previous Transtacker model used pairs of proximity sensors to indicate the position of zero and 180 degrees, but as bales can vary in size their travel couldn't be monitored accurately if they were larger or smaller than the specified size. This variance in bale size could cause the machine to freeze and reliability therefore became an issue.
"What we needed was a programmable sensor capable of providing a safe area within the function that would allow the machine to continue, and this is what the Penny + Giles sensors give us." says Paul. "The contactless Hall effect SRH501P rotary position sensors enable us to increase or decrease the functional sensitivity and introduce error codes that, when detected, allow the machine to continue within safe limits."
A list of systems options was presented by controls specialist Tedd Engineering and reviewed by Big Bale South, whose engineering team is experienced in the many different rotary sensors available. Significantly, within ten minutes of the Penny + Giles SRH501P rotary position sensor being fitted to and operating on the Transtacker, the team decided it was the one for the job!
"It solved every problem instantly." says Paul. "Among the options presented to us were no-contact types called snail shells but when there are gaps between sensors, especially in agricultural applications where conditions are incredibly harsh, they often get mud and crops on them and stop working. We now always specify that any sensors used must have a direct mechanical link with the function."
Once the length of the arm and other details of the specification were calculated and they had the degrees of travel needed, Penny + Giles were able to factory-programme the sensor.
"We needed a system that would tell us where every function was at all times. What we now have, compared to the previous proximity sensors, is fantastic. In effect, the Penny + Giles rotary position sensor has given us fully-programmable functionality."
The SRH501P rotary position sensors are used on three functions. The first is the zero to 180 degrees pick-up function, which lifts the bale from the ground and places it onto the machine. The second function controls the turntable, which can perform a straight vertical lift at 90 degrees. Alternatively, it can perform the third function, which is to lift and rotate through 90 degrees.
As well as rotary position sensors, Penny+ Giles JC6000 multi-axis joystick controllers were also specified for the Transtacker. These are currently programmed with only four of the six available axes because Big Bale's engineers opted to future-proof the system with expandable operating capacity. The JC6000 joystick controller is coupled to a display unit in the tractor cab, which acts as a virtual terminal for the trailer's 'black box' containing the machine's software.
The control system is designed to make life as easy as possible for operators and enables them to simply push the joystick forward to begin the trailer's operation. For the first function, the Transtacker lifts the bale onto the turntable, releases it and returns to position ready to pick up the next bale. The tractor doesn't even need to stop to collect bales. The next function is initiated by pulling the joystick back, which lifts the turntable, rotates the bale and places it onto the back of the trailer. If bales need to be lifted without rotating them, the operator simply actuates one of the joysticks buttons while pulling the joystick back.
The display unit shows four joystick functions at all times and has five menu buttons. Pressing and holding any of the menu buttons changes the screen to show four different functions, which increases the functionality of the buttons on the JC6000 from four to a total of sixteen.
Commenting for Tedd Engineering, Richard Hooper says: "We specified Penny + Giles joysticks because we know they are well made, well engineered units and provide Can (J1939) output. The SRH501P rotary position sensors were also very easy to integrate and the range of options is good so we knew we could immediately obtain the electrical output required to work with our existing circuit board."
He adds that the old proximity sensors didn't provide enough information across the full travel on the machine's functionality because they were set a few degrees off the full travel of the system. This meant the system had only a few degrees within which to decelerate. By contrast, an angular sensor like the Penny + Giles SRH501P knows where it is at all times and can control deceleration accurately.
Paul Bowles comments that, equally important for an agricultural application and especially for the Transtacker engineering team, was the mechanical robustness and generally rugged design of the Penny + Giles sensors and joystick controllers.
Designed to provide an easy, simple and efficient way of collecting and stacking bales in the field, the Big Bale Transtacker takes full advantage of the functionality available with the Penny + Giles control system to make the operator's job easier and ensure safer operation. Examples include enabling the Transtacker's new and improved pick-up function to be adjusted without the operator leaving the cab and ensuring that, for safety, the machine's guide bar is automatically retracted when 'Road Mode' is selected. In addition, when the auto pick-up function on the JC6000 is activated, large double tines penetrate the bales holding them securely on the pick-up frame and lifting them clear of the ground without stopping or slowing the Transtacker's forward movement.
For further information, e-mail: jwranovics@curtisswright.com or view website: www.cwcontrols.com or www.pennyandgiles.com Refer to page 193
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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.
For further information, e-mail: jwranovics@curtisswright.com or view website: www.cwcontrols.com or www.pennyandgiles.com Refer to page 193
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