Novatech has supplied a wide variety of bespoke loadcells and torque transducers for use in robotics.

Applications involving robotics or animatronics often present a unique challenge in terms of design due to the complex articulated movements and intricate tasks that these items are intended to perform. More so than with most other applications, it is crucial to understand the full dynamics of the system to correctly specify the required mechanical properties of the loadcell. Even a simple robot arm for automated manufacturing tasks will be able to move in a way that will subject any loadcell within the design of the arm to varying combinations of extraneous loads, moments and force couples. The inertia as a result of the arms movements, both accelerating and decelerating, will also cause peak forces that may be beyond normal expected operating ranges. These issues are only accentuated when the robot arm is interacting with any kind of payload as this can further add to the cantilever load and increase the moments acting on the loadcell.

As well as accounting for all of the possible loading conditions throughout the full range of movement, the design of loadcells for integration within robotics must allow for the routing of various power cables and/or hydraulics. In the case of animatronics and humanoid robots it is also necessary to give thought to aesthetics and how the design of the loadcell lends itself to the overall look of the end product. This can result in a loadcell that must conform to a very restricted space envelope while still providing the structural strength to cope with the mechanical demands of the application.

To date we have been involved in applications including:

• Force measurement in robot arms for manufacturing, packaging and quality acceptance
• Torque feed back control for articulated joints in humanoid robots
• Motion control of animatronics for film and theme park attractions

Novatech have had great success with new and innovative designs that have provided high performance loadcells despite difficult design restrictions. We are particularly proud of our 'torque discs' for harmonic drives that manage to provide less than 0.5% measurement error despite an average loadcell thickness in the region of 8mm. This has allowed them to be integrated into realistic looking humanoid robots and animatronics, as the torque transducer does not drastically increase the space required for the articulated joint. We have also provided loadcells that, despite severe extraneous loading conditions, are able to detect the variance in weight from a single missing screw in a flat pack self assembly item. This was part of an automated quality check during transfer from a production line to fulfilment, handled at speed by a robot arm with a vacuum controlled grip mechanism. The loadcells needed to cope with a lot of inertia and allow the routing of air lines through the centre of the loadcell bodies without adversely effecting their structural strength.

If you have an application involving robotics of any kind that requires force and/or torque measurement, please contact one of our engineers. They will require detailed information about the dynamics of the application and will be more than happy to offer any advice they can to ensure that the optimum loadcell solution is achieved.