Colloquium announcement

Faculty of Engineering Technology

Department Applied Mechanics
Master programme Mechanical Engineering

As part of his / her masterassignment

Martijn (M.C.) Snippe

will hold a speech entitled:

Cheetah robot leg mechanism: analysis, design and cost of transport

RoomCarré 2L


Many legged robots nowadays consist out of fully actuated joints to induce locomotion, which results in complicated control algorithms. The FREEQ project aims to design a Fast-Running, Energy-Efficient Quadruped based on morphological computation, which shifts the intelligence for locomotion from ‘brain’ to ‘body’. This is done by creating geometrical interconnections of elements such as springs  and inertias with the use of a simple actuator. The dynamics of a real cheetah is analysed and used to extract the core principles of locomotion for the robot design.

This project specifically focuses on the function of the leg. It is proven that a SLIP based leg mechanism design, with the help of simple actuators and simple control (mostly open loop), can induce locomotion in two directions (forward and backwards). The stride frequency, stride length and leg stiffness can be varied to change the forward velocity, but also the energy consumption in a roughly predictable way. The cost of transport, which is a measure for the efficiency of the locomotion, can be kept at a minimum by increasing the leg stiffness when the stride length is made larger to increase the forward velocity of the robot. Furthermore it is shown that the leg stiffness is inseparable from the stride frequency since it should increase when the stride frequency is increased for stable jumping behaviour. The jumping height is almost uncoupled of the stride length during acceleration of the robot, while the jumping height decreases when the stride frequency increases.