Torque Feedback Device Simulates Hydraulic Position/Velocity Feedback

Danaher Motion’s Torque Feedback Device (TFD) meshes tactile and position or velocity feedback with a steering wheel interface in an IP66 rated package. The TFD provides electronic vehicle system, personal mobility and mobile off-highway machine builders the ability to create vehicles and machines capable of delivering the performance and maintenance benefits found in electric or steer-by-wire systems with the tactile response of a hydraulic system, according to the company’s press release.  

Since the product’s design integrates major components, the result is a more compact, modular device capable of high torque densities and energy efficiency in use, as well as making the device easy to scale to specific application requirements. The TFD comes in five versions that range in torque densities from 2.5 Nm to 20 Nm, available as a stand-alone or integrated vehicle system component. When tested, their life lasted over 10,000,000 revolutions at 120 rpm, and they are designed to function in ambient temperatures from -35 degrees Celsius to 60 degrees Celsius.  Redundant sensors are a feature that make shaft feedback dependable and provide field serviceability. Friction materials and an electromagnetic actuation system provide a variable torque output proportional to a DC input for steering and other by-wire applications. Typical steer-by-wire applications include electric vehicles like lift trucks, golf carts, pallet trucks, floor sweepers and cleaning equipment. Other machines steer-by-wire systems are found in are turf and garden equipment, aerospace appliances, construction equipment and marine vehicles.  

 “The Torque Feedback Device provides input to a controller that commands the actuation mechanism in steering and other by-wire applications. The device also provides continuously variable torque output to simulate the ‘feel’ that users of hydraulic systems are comfortable with, allowing operators to more easily adapt to an electric-steer or steer-by-wire vehicle system. With legacy electric steering systems, this functionality either didn’t exist, was too complex or had to be developed and implemented by the vehicle manufacturer,” says product manager Geoff Rondeau.