Slip control via active suspension for optimization of braking and accelerating of a vehicle
AssigneeClearMotion, Inc.
InventorsAditya Chandrashekhar Chetty, Allen Chung-Hao Chen
Life of this patent
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Abstract
System and method for improving braking efficiency by increasing the magnitude of a frictional force between a tire of a vehicle wheel and a road surface. Braking efficiency may be improved by controlling the normal force applied on the wheel, with an active suspension actuator, based on the wheel's slip ratio.
Claims32
A method for controlling an active suspension system of a vehicle, wherein the active suspension system includes an actuator, and wherein the vehicle includes a wheel, the method comprising:
- (a) determining (e.g., by a controller, by a set of one or more controllers) (e.g, during a braking event) a slip ratio of the wheel of the vehicle (e.g, during a braking event);
- (b) based at least in part on the determined slip ratio, determining (e.g., by the controller, by the set of one or more controllers) a command (e.g., a command force, a command pressure, a command voltage, a command current);
- (c) outputting the command (e.g., from the controller, from the set of one or more controllers) to the actuator of the active suspension system.
The method of any of the preceding claims, wherein the determined command is based at least in part on a product of the determined slip ratio times a slip gain.
The method of any preceding claim, further comprising:
- measuring an aspect of vertical motion of a second portion of the vehicle (e.g., a second corner of the vehicle), and wherein the command is determined based at least in part on the aspect of vertical motion.
The method of any of the preceding claims, wherein application of the output force (e.g., to the first portion and/or to the second portion of the vehicle) results in a decrease in the slip ratio of the wheel.
A method for controlling an active suspension system of a vehicle having a wheel, the method comprising:
- applying, with an actuator of the active suspension system associated with the wheel, a force to a portion of the vehicle (e.g., to a wheel assembly that includes the wheel, to a portion (e.g., a corner) of the vehicle body), wherein the applied force is determined (e.g., by a controller, by a set of controllers) based at least in part on an observed slip ratio of the wheel.
A method for controlling an actuator of an active suspension system of a vehicle, the method comprising
- estimating a slip ratio of a wheel of the vehicle at a given time;
- comparing the estimated slip ratio with a threshold slip ratio;
- upon determining that the estimated slip ratio exceeds the threshold slip ratio:
- applying, with an actuator of the active suspension system, a force to the wheel of the vehicle to increase a normal load applied to the wheel.
A method for controlling an active suspension system in a vehicle, the method comprising:
- (a) while operating a vehicle, applying a braking force to a wheel of the vehicle to counteract rotation of the wheel, thereby resulting in an increase in a slip ratio of the wheel;
- (b) subsequently applying, with an actuator of the active suspension system, a second force to a portion of the vehicle, wherein application of the second force results in a decrease in the slip ratio of the wheel.
A method for controlling an active suspension system of a vehicle having a wheel, the method comprising:
- (a) measuring (e.g., with an accelerometer) an aspect (e.g., an acceleration, a velocity, magnitude) of motion (e.g., of vertical motion) of a first portion of the vehicle (e.g., of a corner of a body of the vehicle);
- (b) measuring one or more vehicle parameters (e.g., wherein the one or more vehicle parameters includes at least one of, at least two of, at least three of, or at least four of:
- a fluidic pressure of a brake cylinder of the vehicle or a rate of change thereof, a position of the acceleration pedal or a rate of change thereof, a position of a brake pedal or a rate of change thereof, and/or a position of a steering wheel or a rate of change thereof);
- (c) determining, based at least in part on a set of one or more vehicle parameters, a value of a gain;
- (d) determining (e.g., with one or more controllers) a command based at least in part on a product of the aspect of motion times the gain;
- (e) outputting the command (e.g., from the one or more controller) to an actuator of the active suspension system;
- (f) in response to the actuator receiving the command:
- applying, with the actuator of the active suspension system, an output force to a first portion of the vehicle (e.g., a wheel assembly that includes the wheel, a portion (e.g., a corner) of the vehicle body).
A vehicle comprising:
- a vehicle body;
- a plurality of wheels, including a first wheel associated with a first corner of the vehicle body and a second wheel associated with a second corner of the vehicle body;
- an active suspension system, wherein the active suspension system includes:
- a first actuator configured to apply a first force to the first wheel in response to a first command from a first controller;
- and
- a second actuator configured to apply a second force to the second wheel in response to a second command from a second controller;
- a set of one or more controllers, wherein the set of one or more controllers includes the first controller, and wherein the set of one or more controllers is configured to:
- determine a first slip ratio of the first wheel of the vehicle;
- based at least in part on the first slip ratio, determine a first command force;
- command the first actuator to apply the first command force to the first wheel.
Dependencies are inferred from the claim text.