Motion Applications
Robotic Wheel Drive means controlling wheels used to propel robotic devices such as warehouse robotics, rovers, agricultural robots, robotic lawn mowers and a wide array of mobile devices. Some such devices have two primary drive wheels but three, four and even higher numbers of drive wheels are possible. The unique motion control application that ties these machines together is the challenge of slip control and navigation over uneven and physically diverse terrain.
In this Motion Application:
- Explore Design Considerations & Techniques
The motion control challenge involved with wheel-driven mobile devices differs in one very important respect from virtually all other motion control problems: wheels are not solidly attached to the surfaces they contact and rely on friction for creating motion. This means controlling the motor's angle position, velocity, or torque output doesn't allow the controller to perfectly predict the location and trajectory of the mobile device. - Examine Application Architecture
The diagram below shows a generalized outer loop controller which uses the qa (actual robot position to generate the linear and angular velocities the robot has to follow to reach the trajectory). This robot motion information is transformed to velocity commands for each driven wheel and output to a velocity loop. The velocity loop, one for each driven wheel, inputs via an encoder the wheel position from which it derives the velocity and then calculates a velocity error which is passed through a PI (proportional, integral) filter and output as a torque command to the amplifier. - View Motion Control Solutions
Since 1994 Performance Motion Devices products have been used in a range of mobile applications including welding inspection robots, agricultural robots, bomb disposal robots, construction robots, rovers and more. PMD’s ultra-compact and powerful N-Series ION Drive is especially well suited for robotic wheel control, as are the MC58113 IC and Juno Family of ICs.
Click here to see more.