Robot Kinematics Library

This library calculates the forward and inverse kinematics for an arbitrary robot arm in an arbitrary number of dimensions.

Install

This library depends on NumIdr, which must be installed first.

To install:

git clone https://github.com/kiana-S/idris2-robotlib
cd idris2-robotlib
idris2 --install robotlib.ipkg

Tutorial

import Kinematics.Forward
import Kinematics.Inverse

A robot arm is a value of type ArmElement n, where n is the number of dimensions the robot operates in. An arm is constructed by chaining together arm elements left-to-right using the <+> operator. Some examples of arm elements are:

• link, a link in a direction given by a vector
• linkX, a link in the +X direction given its length
• revolute2D, a 2D revolute joint
• revoluteX, revoluteY, revoluteZ, 3D revolute joints along the corresponding axis

For example, here is a simple SCARA robot arm in 2D space:

scara : ArmElement 2
scara = revolute2D (-pi/2) (pi/2) <+> linkX 5
    <+> revolute2D (-pi/2) (pi/2) <+> linkX 7

The joint constructors take as arguments their limit angles. All angles are given in radians.

To calculate the forward kinematics of a robot arm, use the function forward, which takes in an arm and a vector of joint values. For example:

endPos : Maybe (Point 2 Double)
endPos = forward scara (vector [2.1, 1.6])

If any of the joint values are outside of the respective joint's limits, the function will return Nothing.

To numerically calculate the inverse kinematics of a robot arm, use the function inverse. It takes in the robot arm and an endpoint, along with a "fuel" value that limits how many iterations the algorithm performs, one of forever or (limit n).

calcInverse : Maybe (Vector 2 Double)
calcInverse = inverse forever scara (point [9, 4])

If the algorithm cannot find any solutions within the joint limits, it will return Nothing.