LIGHTS, CAMERA, AUTOMATION....
31 October 2012
Wittenstein’s TPM+ integrated servo motor and precision planetary gearhead combo is finding a niche in special purpose motion control robotic cameras used by special effects companies for filming on location
WORLD WIDE USE
Mark Roberts Motion Control rigs and equipment are used on commercials, music videos and feature films all over the world, including Snow White & The Huntsman, The Muppets, Sherlock Holmes: A Game of Shadows, and Harry Potter and the Deathly Hallows: Parts 1 and 2.
LIGHTS, CAMERA, AUTOMATION....
The most obvious benefit of the integrated servo motor and precision planetary gearhead combination which make up the TPM+ is the massive space saving achieved by the innovative construction. Space is at a premium at the extremity of the Milo’s arm, so the fact that the overall length of the TPM+010 is less than 170mm and can transmit 100Nm is a perfect solution.
Other axes on the Milo rig include the linear track, which is rack and pinion operated for the traversing of the robot base up to 2m/s along the track. There are 10 further axes of motion, including rotate, lift, arm extend, pan, tilt and roll which incorporate ballscrews, couplings, precision gearheads and industrial gears In purely engineering terms, perhaps the most profound benefit is the improved torsional rigidity of the drive chain compared to that of a conventional gearbox coupled to a servo motor. All too often, system designers insist on extremely low backlash but disregard the importance of high stiffness for highly dynamic servo applications. However, the TPM+ offers both extremely low backlash and exceptional stiffness. Moreover, connecting the motor to the gearhead without a coupling reduces the moment of inertia by approximately 40%. This further improves the power density, delivering huge power in a small space envelope.
Robotic applications such as axle actuators for paint spraying robots or Delta 3 robots for high speed pick and placement of components are applications for which these rotary servo actuators are suited. The TPM+ cut its teeth with a linear rack and pinion application used in the injection moulding and plastics industry.
Because the Wittenstein pinions bolt directly to the rotary flange of the TPM+, in combination with a rack, they can replace a rod and crank to close the press on extrusion blow moulding machines, offering 11kN of linear force with this system.
The TPM+ is available in sizes ranging from the 30Nm frame size which has a 75mm diameter body up to the 3000Nm high torque version which has a 160mm diameter rotary flange. In a new development, Wittenstein will shortly make available the Sumo size units which have maximum acceleration torques of up to 10,000Nm and are based on the output style of the TP+ gearheads.
TPM units are compatible with almost every servo controller in the UK, including Siemens, Rockwell, B&R, Bosch, and Control Techniques. The available feedback devices include absolute encoders (such as Hiperface or EnDat), as well as incremental encoders and resolvers. Other options include holding brakes and a choice of DC bus voltage and temperature sensors.
- The TPM+ is utilised in the tilt axis at the outer arm – the axis which allows the camera to reach otherwise impossible positions
- The rotary servo actuators are suited to robotic applications such as axle actuators for paint spraying robots or Delta 3 robots for high speed pick and placement of components