Systems and methods of clamp compensation

A method, comprising:

• applying a clamp element drive signal to a clamp element to engage a mover element, the clamp element and a shear element together comprising a drive unit wherein a contact surface of the drive unit contacts a surface of the mover element at a non-perpendicular contact angle causing the mover element to move by a first displacement;
• determining the first displacement of the mover element;
• determining a first compensation signal to be applied the shear element based at least in part on the first displacement;
• applying an initial shear element drive signal to the shear element and the clamp element drive signal to the clamp element to move the mover element a second distance;
• determining a second displacement of the mover element in response to the first compensation signal and the clamp element drive signal, the second displacement due at least in part to the non-perpendicular contact angle;
• and
• comparing the second displacement to a preselected threshold;
• for a second displacement less than the preselected threshold, combining the first compensation signal with the initial shear element drive signal to produce a modified shear element drive signal;
• and
• for a second displacement greater than the preselected threshold, determining a second compensation signal to be applied to the one or more drive unit shear elements.