love.physics.newMotorJoint
Creates a joint between two bodies which controls the relative motion between them.

Position and rotation offsets can be specified once the MotorJoint has been created, as well as the maximum motor force and torque that will be be applied to reach the target offsets.
joint = love.physics.newMotorJoint( body1, body2, correctionFactor )
body1 Body The first body to attach to the joint.
body2 Body The second body to attach to the joint.
correctionFactor (0.3) number The joint's initial position correction factor, in the range of 1.
joint MotorJoint The new MotorJoint.
joint = love.physics.newMotorJoint( body1, body2, correctionFactor, collideConnected )
body1 Body The first body to attach to the joint.
body2 Body The second body to attach to the joint.
correctionFactor (0.3) number The joint's initial position correction factor, in the range of 1.
collideConnected (false) boolean Specifies whether the two bodies should collide with each other.
joint MotorJoint The new MotorJoint.