主权项 |
1. Seismic shaker (1) for exerting an excitation force on the ground, comprising:
a base plate (3) for placement on the ground (4) through which the excitation force is exerted on the ground, a reaction mass (5), a resilient construction (7) and parallel thereto an actuator (9) through which the reaction mass is connected to the base plate, a controller unit (15) which is connected to and controls the actuator, a sensor (17) measuring a parameter of the motion of the reaction mass relative to the base plate and connected to the controller unit, a first comparison unit (19) which is present between the controller unit and the sensor, and that sends a difference signal (21) that is equal to the difference between the measured value (27) of the parameter, and a value of the parameter set in the first comparison unit (25), a control unit (29) which is present between the first comparison unit and the controller unit, and that as a function of the difference signal computes a correction value (31), and a second comparison unit (33) which is present between the control unit and the controller unit, and sends out a sum signal (39) which is equal to the sum of the correction value and a desired value of the excitation force to be exerted set in the second comparison unit (35),characterized in that the sensor (17) is a displacement sensor and the parameter is the displacement of the reaction mass. |