An actuator system for positioning a valve or device with a mechanical input comprising: a fluid operated actuator comprising an output coupled to the mechanical input of the valve, a feedback element for mechanically indicating a position of the valve or device, and inputs for actuating fluid, such that fluid at the inputs causes the fluid operated actuator to move in opposing directions; and a mechanical position feedback member (130, 2c, 2d) coupled to the feedback element of the fluid operated actuator; and an activation fluid valve (150, 6) having outputs coupled to the inputs of the fluid operated actuator; and a proportional control valve (30, 60, 70, 80); characterized in that: the activation fluid valve further comprises at least three distinct positions and an infinite number of intermediate positions; a first opposing force input on a first side of the activation fluid valve, the activation fluid valve (150, 6), mechanically coupled to the mechanical position feedback member (130, 2c, 2d) through a resilient element on the first side of the activation fluid valve; and a second opposing force input comprising a modulated pilot pressure from a proportional control valve (30, 60, 70, 80) through a pilot port on a second side of the activation fluid valve (150,6); the first opposing force input and the second opposing force input being reciprocal to each other such that the position of the activation fluid valve (150, 6) is controlled by a balance between the first opposing force input from the mechanical feedback member (130, 2c, 2d) and the second opposing force input from the modulated pilot pressure. a fluid operated actuator comprising an output coupled to the mechanical input of the valve, a feedback element for mechanically indicating a position of the valve or device, and inputs for actuating fluid, such that fluid at the inputs causes the fluid operated actuator to move in opposing directions; and a mechanical position feedback member (130, 2c, 2d) coupled to the feedback element of the fluid operated actuator; and an activation fluid valve (150, 6) having outputs coupled to the inputs of the fluid operated actuator; and a proportional control valve (30, 60, 70, 80); the activation fluid valve further comprises at least three distinct positions and an infinite number of intermediate positions; a first opposing force input on a first side of the activation fluid valve, the activation fluid valve (150, 6), mechanically coupled to the mechanical position feedback member (130, 2c, 2d) through a resilient element on the first side of the activation fluid valve; and a second opposing force input comprising a modulated pilot pressure from a proportional control valve (30, 60, 70, 80) through a pilot port on a second side of the activation fluid valve (150,6); the first opposing force input and the second opposing force input being reciprocal to each other such that the position of the activation fluid valve (150, 6) is controlled by a balance between the first opposing force input from the mechanical feedback member (130, 2c, 2d) and the second opposing force input from the modulated pilot pressure. at least three distinct positions and an infinite number of intermediate positions; a first opposing force input on a first side of the activation fluid valve, the activation fluid valve (150, 6), mechanically coupled to the mechanical position feedback member (130, 2c, 2d) through a resilient element on the first side of the activation fluid valve; and a second opposing force input comprising a modulated pilot pressure from a proportional control valve (30, 60, 70, 80) through a pilot port on a second side of the activation fluid valve (150,6); the first opposing force input and the second opposing force input being reciprocal to each other such that the position of the activation fluid valve (150, 6) is controlled by a balance between the first opposing force input from the mechanical feedback member (130, 2c, 2d) and the second opposing force input from the modulated pilot pressure.