# US 9,038,526 B2 · Kinematic control in a hydraulic system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,038,526 B2 - Document ID: US9038526B2 - Status: Granted - Kind: B2 - Application number: 13/321,225 - Filed: 2010-05-28 - Published: 2012-04-19 - Granted: 2015-05-26 - Earliest claimed: 2009-06-19 - Assignees: Husky Injection Molding Systems Ltd. - Applicants: Mingyu Liu; William Harold Howlett; Daoshan Ouyang - Inventors: Mingyu Liu; William Harold Howlett; Daoshan Ouyang - Web page: https://patentgrep.com/patent/US9038526B2 ## CPC - F15B 11/0423: {by controlling pump output or bypass, other than to maintain constant speed} - F15B 2211/755: Control of acceleration or deceleration of the output member - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR ## Abstract A hydraulic system is provided, having a pump, operably connected to a motor. It also comprises a controller-driven hydraulic actuator, operably connected to the pump and a hydraulic valve, operable to direct hydraulic fluid to and from either a rod side or a cylinder side of the hydraulic actuator. Rod and cylinder side pressures are pre-defined based on the instantaneous acceleration or deceleration required. Decelerating the hydraulic actuator could involve maintaining the current pressure in the meter-out side of the hydraulic actuator and decreasing the current pressure in the meter-in side by varying the speed of the pump. Deceleration of the hydraulic actuator could also include decreasing pressure on the meter-in side of the hydraulic actuator at a higher rate than on the meter-out side. Acceleration is achieved using a similar approach. ## Claims ### Claim 1 A method for decelerating a hydraulic actuator, the method comprising: performing one of maintaining pressure and decreasing the pressure in a meter-out side of the hydraulic actuator; decreasing pressure on a meter-in side of the hydraulic actuator, the hydraulic actuator decreasing pressure on the meter-in side more rapidly than on the meter-out side of the hydraulic actuator; and wherein decreasing the pressure on the meter-in side of the hydraulic actuator is achieved by adjusting a speed in a pump. ### Claim 2 (depends on 1) The method of claim 1, wherein a pressure setpoint on the meter-out side of the hydraulic actuator is calculated as a sum of a minimum meter-in pressure and a required maximum deceleration pressure. ### Claim 3 (depends on 2) The method of claim 2, wherein the minimum meter-in pressure on the meter-in side of the hydraulic actuator is calculated to avoid a vacuum within the hydraulic actuator during deceleration. ### Claim 4 (depends on 3) The method of claim 3, wherein a flow setpoint on the meter-out side is calculated as a speed setpoint multiplied by a cross-sectional area of the hydraulic actuator on the meter-out side. ### Claim 5 (depends on 4) The method of claim 4, wherein the speed of the pump is regulated by an open-loop control that calculates the speed of the pump from a velocity profile plus jerk compensation. ### Claim 6 (depends on 4) The method of claim 4, wherein the speed of the pump is regulated by a closed-loop control which calculates the speed of the pump from a velocity profile with jerk compensation plus a contribution from a PID controller. ### Claim 7 A method for accelerating a hydraulic actuator, the method comprising: performing one of maintaining pressure and increasing the pressure in a meter-out side of the hydraulic actuator; increasing pressure on a meter-in side of the hydraulic actuator, the hydraulic actuator increasing pressure on the meter-in side more rapidly than on the meter-out side of the hydraulic actuator; and wherein increasing the pressure on the meter-in side of the hydraulic actuator is achieved by adjusting a speed in a pump. ### Claim 8 (depends on 7) The method of claim 7, wherein a pressure setpoint on the meter-out side of the hydraulic actuator is calculated as a sum of a minimum meter-in pressure and a required maximum acceleration pressure. ### Claim 9 (depends on 8) The method of claim 8, wherein the minimum meter-in pressure on the meter-in side of the hydraulic actuator is calculated to avoid a vacuum within the hydraulic actuator during acceleration. ### Claim 10 (depends on 9) The method of claim 9, wherein a flow setpoint on the meter-out side is calculated as a speed setpoint multiplied by a cross-sectional area of the hydraulic actuator on the meter-out side. ### Claim 11 (depends on 10) The method of claim 10, wherein the speed of the pump is regulated by an open-loop control that calculates the speed of the pump from an velocity profile plus jerk compensation. ### Claim 12 (depends on 10) The method of claim 10, wherein the speed of the pump is regulated by a closed-loop control which calculates the speed of the pump from a velocity profile with jerk compensation plus a contribution from a PID controller. ### Claim 13 A hydraulic system, comprising: a pump, operably connected to a motor; a hydraulic actuator, operably connected to the pump; a hydraulic valve, operable to direct hydraulic fluid to and from either a rod side or a cylinder side of the hydraulic actuator; and a controller, configured to alternatively accelerate and decelerate the hydraulic actuator by: performing one of maintaining a current pressure and adjusting the pressure in a meter-out side of the hydraulic actuator; adjusting pressure on a meter-in side of the hydraulic actuator at a higher rate than on the meter-out side of the hydraulic actuator; and wherein adjusting the pressure on the meter-in side of the hydraulic actuator is achieved by adjusting a speed in the pump. ### Claim 14 (depends on 13) The hydraulic system of claim 13, wherein the controller is operable to control acceleration by increasing the speed of the pump so that the pressure on the meter-in side is greater than on the meter-out side of the hydraulic actuator. ### Claim 15 (depends on 14) The hydraulic system of claim 14, wherein the controller is operable to control deceleration by decreasing the speed of the pump so that the pressure on the meter-in side is less than on the meter-out side of the hydraulic actuator. ### Claim 16 (depends on 15) The hydraulic system of claim 15, wherein a pressure setpoint on the meter-out side of the hydraulic actuator is calculated by the controller as a sum of a minimum meter-in pressure and a required maximum deceleration pressure. ### Claim 17 (depends on 16) The hydraulic system of claim 16, wherein the pressure setpoint on the meter-in side of the hydraulic actuator is greater that that required to avoid a vacuum within the hydraulic actuator during deceleration. ### Claim 18 (depends on 17) The hydraulic system of claim 17, wherein a flow setpoint on the meter-out side is calculated by the controller as a speed setpoint multiplied by a cross-sectional area of the hydraulic actuator on the meter-out side. ### Claim 19 (depends on 18) The hydraulic system of claim 18, wherein the speed of the pump is regulated by an open-loop control that calculates the speed of the pump from a velocity profile plus jerk compensation. ### Claim 20 (depends on 18) The hydraulic system of claim 18, wherein the speed of the pump is regulated by a closed-loop control which calculates the speed of the pump from a velocity profile with jerk compensation plus a contribution from a PID controller.