Active suspension systems and components using piezoelectric sensing and actuation devices

A system for controlling the stiffness and damping of a vehicle suspension spring comprising:

• a) a spring steel body forming an electrically conductive metal matrix;
• b) a plurality of piezoelectric particles embedded within said matrix, said piezoelectric particles in said metal matrix including means for transmitting an input signal in response to a mechanical stress applied to said spring body, and including means for receiving an excitation signal to effect a variable force on said spring body;
• c) sensor means for generating a plurality of control signals representative of certain driving conditions;
• d) amplifier means, including a first amplifier electrically connected to said piezoelectric particles for receiving and amplifying the input signal from said piezoelectric particles, and a second amplifier for receiving and amplifying the control signals representative of selected driving conditions from said sensor means;
• and
• e) control means connected to the first amplifier for receiving and analyzing the input signal, and connected to the second amplifier for receiving and analyzing the control signals said control means transmitting, in response to the selected driving conditions, a modulated excitation signal to said piezoelectric particles, the modulated excitation signal from said control means varying the force exerted by said piezoelectric particles on said spring body in response to an instantaneous motion of said spring body caused by the mechanical stress, which controls the damping of said spring body, and simultaneously varying the force exerted by said piezoelectric particles on said spring body in response to the control signals from said sensor means, which controls the stiffness of said spring body.

An active suspension system having stiffness and damping control, said suspension system comprising:

• a) a spring for supporting a chassis;
• b) a plurality of piezoelectric elements integrally affixed to said spring, said piezoelectric elements including means for sensing a mechanical stress applied to said spring and generating an input signal, and means for receiving an excitation signal to effect a variable force on said spring;
• c) sensor means mounted on the chassis for sensing a plurality of operational conditions and generating a plurality of control signals representative of selected operational conditions;
• d) amplifier means, including a first amplifier electrically connected to said piezoelectric elements for receiving and amplifying the input signal from said piezoelectric elements, and a second amplifier for receiving and amplifying the control signals representative of selected operational conditions from said sensor means;
• e) controller means electrically connected to the second amplifier for receiving and analyzing the control signals, and electrically connected to the first amplifier for receiving and analyzing the input signal from said piezoelectric elements, said controller means comparing the control signals and the input signal with a set of preprogrammed instructions, and for generating a feedback control signal;
• and
• f) power supply means for receiving the feedback control signal from said controller means and transmitting, in response to the selected operational conditions, an excitation signal to said piezoelectric elements, the excitation signal from said power supply means varying the force exerted by said piezoelectric elements on said spring in response to an instantaneous motion of said spring caused by the mechanical stress, which controls the damping of said spring, and simultaneously varying the force exerted by said piezoelectric elements on said spring in response to the control signals from said sensor means, which controls the stiffness of said spring.