Robot that ‘gallops like a horse’

The Pegasus robot which was created by students during a research project has legs that can gallop almost like those of a horse - due to DC motors and DC motor controllers by maxon.

As part of a research project at the Swiss Federal Institute of Technology, Zurich, the autonomous robot called Pegasus was created. With its telescopic legs, it can move across vast distances. The legs are designed for moving in a dynamic trot and can achieve top performance with low energy consumption through its drive technology.

The robot has a modular design and can be used for a wide range of applications. Each module consists of two legs; hence he can be sent on his journey with two, four or even six legs. During the timeframe of the project, three modules were built.

In each leg, a maxon RE40 DC motor drives the spindle that is responsible for extending and retracting the leg. Additionally, an EC 4-pole DC brushless motor controls the rotational degree of freedom in the hip module (connecting part between two leg modules). It is the 200 DC brushless motor that makes it possible for the entire leg to turn.

Special winding and the 4-pole magnets of the drives deliver high power per unit of volume and weight. The motors have no cogging torque, an efficiency of more than 90% and good control dynamics. The metal housing ensures good heat dissipation and mechanical stability.

Two different positioning motor controllers are used to control the robot. One of these is the EPOS 24/2 controller which is used to control additional sensor interfaces. This position controller was specially developed for commands and control functions in CANopen networks. Additionally, this controller has been equipped with good motion control functions.

The controller can synchronously move along a path specified by setpoints.

The EPOS2 70/10 controller used is specially tailored to the brushed DC motors with Hall sensors and encoders from 80 to 700 W.

The target of achieving a distance of 10 km in less than 10,000 seconds with a single battery charge is within grasp, according to the institute.