We have been cooperating with customers closely from product development to series production, and providing rapid and exact solution, so that the customer can be free and concentrate on their core business field. We regularly check customer satisfaction and improve it continually. The control device of air suspension was properly arranged to ensure the wheel positional parameters, driving angle and steering system against interface. Statically indeterminate force of guide bar were reduced, which got a best effect of bumper and increase the service life of air spring.