An electrostatic slide clutch comprising: a first sheet electrode; a second sheet electrode oriented parallel to first sheet electrode; a dielectric layer between the first and second sheet electrodes (46A, 46B); and a drive circuit coupled electrically to the first sheet electrode and to the second sheet electrode; characterized in that: the drive circuit includes a pulse-width modulator configured to vary an output pulse width in response to a control signal to apply an alternating voltage to move a variable amount of charge bidirectionally between the first and second sheet electrodes (46A, 46B); and the electrostatic slide clutch includes a displacement sensor responsive to the area of overlap between the first and second sheet electrodes (46A, 46B), wherein the control signal depends upon an output of the displacement sensor and an amount and polarity of charge already separated across the first and second sheet electrodes (46A, 46B), to influence a normal force between the first and second sheet electrodes (46A, 46B), wherein the amount and polarity of the charge already separated across the first and second sheet electrodes (46A, 46B) is stored in a computer coupled operatively to the electrostatic slide clutch. a first sheet electrode; a second sheet electrode oriented parallel to first sheet electrode; a dielectric layer between the first and second sheet electrodes (46A, 46B); and a drive circuit coupled electrically to the first sheet electrode and to the second sheet electrode; characterized in that: the drive circuit includes a pulse-width modulator configured to vary an output pulse width in response to a control signal to apply an alternating voltage to move a variable amount of charge bidirectionally between the first and second sheet electrodes (46A, 46B); and the electrostatic slide clutch includes a displacement sensor responsive to the area of overlap between the first and second sheet electrodes (46A, 46B), wherein the control signal depends upon an output of the displacement sensor and an amount and polarity of charge already separated across the first and second sheet electrodes (46A, 46B), to influence a normal force between the first and second sheet electrodes (46A, 46B), wherein the amount and polarity of the charge already separated across the first and second sheet electrodes (46A, 46B) is stored in a computer coupled operatively to the electrostatic slide clutch. the drive circuit includes a pulse-width modulator configured to vary an output pulse width in response to a control signal to apply an alternating voltage to move a variable amount of charge bidirectionally between the first and second sheet electrodes (46A, 46B); and the electrostatic slide clutch includes a displacement sensor responsive to the area of overlap between the first and second sheet electrodes (46A, 46B), wherein the control signal depends upon an output of the displacement sensor and an amount and polarity of charge already separated across the first and second sheet electrodes (46A, 46B), to influence a normal force between the first and second sheet electrodes (46A, 46B), wherein the amount and polarity of the charge already separated across the first and second sheet electrodes (46A, 46B) is stored in a computer coupled operatively to the electrostatic slide clutch.