Abstract: In the crash test an object having a known mass is propelled along a propulsion path, continuously taking measurements of acceleration, velocity and force allowing a control system, in real time, to calculate the coefficients ai in the expression (a0+a1v+a2v2). The operator selects a velocity vc at which the object should be traveling when the object strikes the barrier. Using the selected velocity vc and values determined for a0, a1 and a2 an operator can determine a release velocity vr where the vehicle can be released from a release point and then coast and decelerating to the velocity vc when the vehicle hits the crash barrier.

Abstract: A wind turbine has a rotor; a hydraulic pump coupled to the rotor, two or more variable displacement hydraulic motors which are driven by fluid flow from the hydraulic pump, at least one generator coupled to the variable displacement hydraulic motors and a closed loop hydraulic oil circuit for carrying pressurized oil from the hydraulic pump to the motors and to return oil to the pump from the motors. A controller in the closed loop hydraulic oil circuit controls the flow of oil in the closed loop circuit and displacement in each of the variable displacement hydraulic motors. Control of flow in and out of the motor for each revolution of that motor controls the flow to the hydraulic pump which has a fixed displacement, thereby controlling its rpm, thereby controlling the rotor rpm. A hydraulic accumulator can be provided in the closed loop.

Abstract: A wind turbine has a rotor; a hydraulic pump coupled to the rotor, two or more variable displacement hydraulic motors which are driven by fluid flow from the hydraulic pump, at least one generator coupled to the variable displacement hydraulic motors and a closed loop hydraulic oil circuit for carrying pressurized oil from the hydraulic pump to the motors and to return oil to the pump from the motors. A controller in the closed loop hydraulic oil circuit controls the flow of oil in the closed loop circuit and displacement in each of the variable displacement hydraulic motors. Control of flow in and out of the motor for each revolution of that motor controls the flow to the hydraulic pump which has a fixed displacement, thereby controlling its rpm, thereby controlling the rotor rpm. A hydraulic accumulator can be provided in the closed loop.