# US 8,788,144 B2 · Braking torque adjustments based on wheel slip > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,788,144 B2 - Document ID: US8788144B2 - Status: Granted - Kind: B2 - Application number: 12/627,604 - Filed: 2009-11-30 - Published: 2011-06-02 - Granted: 2014-07-22 - Earliest claimed: 2009-11-30 - Assignees: GM Global Technology Operations LLC - Applicants: Eric E. Krueger; Kevin S. Kidston; Eric J. Holdorf; Mahir Hodzic - Inventors: Eric E. Krueger; Kevin S. Kidston; Eric J. Holdorf; Mahir Hodzic - Web page: https://patentgrep.com/patent/US8788144B2 ## CPC - B60W 20/13: in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion - B60L 3/10: Indicating wheel slip {; Correction of wheel slip} - B60L 7/18: Controlling the braking effect (B60L7/12, B60L7/14, B60L7/16 take precedence) - B60T 1/10: by utilising wheel movement for accumulating energy, e.g. driving air compressors - B60T 8/17636: {Microprocessor-based systems} - B60W 10/08: including control of electric propulsion units, e.g. motors or generators - B60W 10/184: with wheel brakes - B60W 30/18127: {Regenerative braking} - B60L 2240/461: Speed - B60L 2240/465: Slip - B60T 2270/604: Merging friction therewith; Adjusting their repartition - B60W 20/00: Control systems specially adapted for hybrid vehicles {(hybrid vehicle design, B60K6/00; electric vehicles B60L)} - B60W 2520/10: Longitudinal speed - B60W 2520/26: Wheel slip - B60W 2520/263: Slip values between front and rear axle - B60W 2520/28: Wheel speed - B60W 2540/12: Brake pedal position - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES ## Abstract A method for adjusting braking in a vehicle having wheels and a regenerative braking system is provided. The method comprises the steps of providing regenerative braking torque for the vehicle via the regenerative braking system at a first level if a wheel slip of the vehicle is not present, and providing regenerative braking torque for the vehicle via the regenerative braking system at one of a plurality of modulated levels if the wheel slip is present. Each of the plurality of modulated levels is dependent on a magnitude, a location, or both, of the wheel slip. Each of the modulated levels is less than the first level. ## Claims ### Claim 1 A method for adjusting braking in a vehicle having wheels and a regenerative braking system, the method comprising the steps of: providing regenerative braking torque for the vehicle via the regenerative braking system, via instructions provided by a processor, at a first level if a wheel slip of the vehicle is not present; and providing regenerative braking torque for the vehicle via the regenerative braking system, via instructions provided by the processor, at one of a plurality of modulated levels if the wheel slip is present, each of the plurality of modulated levels being dependent on a location of the wheel slip, each of the plurality of modulated levels being less than the first level. ### Claim 2 (depends on 1) The method of claim 1, wherein the step of providing regenerative braking torque comprises the steps of: reducing regenerative braking torque for the vehicle via the regenerative braking system at a first rate if the wheel slip is present and the magnitude of the wheel slip is less than a predetermined threshold; and reducing regenerative braking torque for the vehicle via the regenerative braking system at a second rate if the wheel slip is present and the magnitude of the wheel slip is greater than the predetermined threshold, the second rate being greater than the first rate. ### Claim 3 (depends on 1) The method of claim 1, wherein the step of providing regenerative braking torque comprises the steps of: reducing regenerative braking torque for the vehicle via the regenerative braking system for a first amount of time if the wheel slip is present and the magnitude of the wheel slip is less than a predetermined threshold; and reducing regenerative braking torque for the vehicle via the regenerative braking system for a second amount of time if the wheel slip is present and the magnitude of the wheel slip is greater than the predetermined threshold, the second amount of time being greater than the first amount of time. ### Claim 4 (depends on 1) The method of claim 1, wherein the wheels comprise a front wheel and a rear wheel, and the method further comprises the steps of: measuring vehicle speeds for one or more of the plurality of wheels; determining whether the wheel slip is present in the front wheel, using the vehicle speeds; and determining whether the wheel slip is present in the rear wheel, using the vehicle speeds. ### Claim 5 (depends on 4) The method of claim 4, wherein the step of providing regenerative braking torque comprises the steps of: providing regenerative braking torque for the vehicle via the regenerative braking system at a second level of the plurality of modulated levels if the wheel slip is present in the rear wheel but not in the front wheel; and providing regenerative braking torque for the vehicle via the regenerative braking system at a third level of the plurality of modulated levels if the wheel slip is present in the front wheel, the third level being greater than the second level. ### Claim 6 (depends on 4) The method of claim 4, wherein the step of providing regenerative braking torque comprises the steps of: reducing regenerative braking torque for the vehicle via the regenerative braking system at a first rate if the wheel slip is present in the rear wheel but not in the front wheel; and reducing regenerative braking torque for the vehicle via the regenerative braking system at a second rate if the wheel slip is present in the front wheel, the second rate being greater than the first rate. ### Claim 7 (depends on 4) The method of claim 4, wherein the step of providing regenerative braking torque comprises the steps of: reducing regenerative braking torque for the vehicle via the regenerative braking system for a first amount of time if the wheel slip is present in the rear wheel but not in the front wheel; and reducing regenerative braking torque for the vehicle via the regenerative braking system for a second amount of time if the wheel slip is present in the front wheel, the second amount of time being less than the first amount of time. ### Claim 8 (depends on 4) The method of claim 4, wherein the step of providing regenerative braking torque comprises the steps of: providing regenerative braking torque for the vehicle via the regenerative braking system at a second level of the plurality of modulated levels if the wheel slip is present in the rear wheel but not in the front wheel; and providing regenerative braking torque for the vehicle via the regenerative braking system at a third level of the plurality of modulated levels if the wheel slip is present in the rear wheel but not in the front wheel, the third level being greater than the second level. ### Claim 9 A method for adjusting braking in a vehicle having wheels and a regenerative braking system, the method comprising the steps of: reducing regenerative braking torque for the vehicle via the regenerative braking system, via instructions provided by a processor, at a first rate of reduction if a wheel slip of the vehicle is present and a magnitude of the wheel slip is less than a predetermined threshold; and reducing regenerative braking torque for the vehicle via the regenerative braking system, via instructions provided by the processor, at a second rate of reduction if the wheel slip is present and the magnitude of the wheel slip is greater than the predetermined threshold, the second rate being greater than the first rate. ### Claim 10 (depends on 9) The method of claim 9, wherein the wheels comprise a front wheel and a rear wheel, and the method further comprises the steps of: measuring vehicle speeds for one or more of the plurality of wheels; and determining whether the wheel slip is present in the front wheel using the vehicle speeds, wherein the step of reducing regenerative braking torque for the vehicle at the second rate of reduction further comprises the step of reducing regenerative braking torque for the vehicle via the regenerative braking system at the second rate of reduction on the further condition that the wheel slip is detected in the rear wheel. ### Claim 11 (depends on 9) The method of claim 9, wherein the vehicle also has a friction braking system, and the method further comprises the steps of: increasing friction braking torque for the vehicle via the friction braking system at a first rate of increase if the wheel slip is present and the magnitude of the wheel slip is less than the first predetermined threshold; and increasing friction braking torque for the vehicle via the friction braking system at a second rate of increase if the wheel slip is present and the magnitude of the wheel slip is greater than the first predetermined threshold, the second rate being greater than the first rate. ### Claim 12 A system for adjusting braking in a vehicle having a plurality of wheels and a regenerative braking system, the system comprising: one or more sensors configured to measure wheel speeds from one or more of the plurality of wheels; and a processor coupled to the one or more sensors and configured to: determine whether and where wheel slip is present using the wheel speeds; and cause the regenerative braking system to provide regenerative braking torque for the vehicle: at a first level if the wheel slip is not present; and at one of a plurality of modulated levels if the wheel slip is present, each of the plurality of modulated levels being dependent on a location of the wheel slip, each of the plurality of modulated levels being less than the first level. ### Claim 13 (depends on 12) The system of claim 12, wherein the processor is further configured to: calculate the magnitude of the wheel slip if the wheel slip is present; and cause the regenerative braking system to reduce regenerative braking torque for the vehicle: at a first rate if the wheel slip is present and the magnitude of the wheel slip is less than a predetermined threshold; and at a second rate if the wheel slip is present and the magnitude of the wheel slip is greater than the predetermined threshold, the second rate being greater than the first rate. ### Claim 14 (depends on 12) The system of claim 12, wherein the processor is further configured to: calculate the magnitude of the wheel slip if the wheel slip is present; and cause the regenerative braking system to reduce regenerative braking torque for the vehicle for: a first amount of time if the wheel slip is present and the magnitude of the wheel slip is less than a predetermined threshold; and a second amount of time if the wheel slip is present and the magnitude of the wheel slip is greater than the predetermined threshold, the second amount of time being greater than the first amount of time. ### Claim 15 (depends on 12) The system of claim 12, wherein the plurality of wheels comprises a front wheel and a rear wheel, and the processor is further configured to: determine whether the wheel slip is present in the front wheel using the wheel speeds; determine whether the wheel slip is present in the rear wheel using the wheel speeds; and cause the regenerative braking system to provide regenerative braking torque for the vehicle: at a second level of the plurality of modulated levels if the wheel slip is present in the rear wheel but not in the front wheel; and at a third level of the plurality of modulated levels if the wheel slip is present in the front wheel, the third level being greater than the second level. ### Claim 16 (depends on 12) The system of claim 12, wherein the plurality of wheels comprises a front wheel and a rear wheel, and the processor is further configured to: determine whether the wheel slip is present in the front wheel using the wheel speeds; determine whether the wheel slip is present in the rear wheel using the wheel speeds; and cause the regenerative braking system to reduce regenerative braking torque for the vehicle: at a first rate if the wheel slip is present in the rear wheel but not in the front wheel; and at a second rate if the wheel slip is present in the front wheel, the second rate being less than the first rate. ### Claim 17 (depends on 12) The system of claim 12, wherein the plurality of wheels comprises a front wheel and a rear wheel, and the processor is further configured to: determine whether the wheel slip is present in the front wheel using the wheel speeds; determine whether the wheel slip is present in the rear wheel using the wheel speeds; and cause the regenerative braking system to reduce regenerative braking torque for the vehicle for: a first amount of time if the wheel slip is present in the rear wheel but not in the front wheel; and a second amount of time if the wheel slip is present in the front wheel, the second amount of time being less than the first amount of time. ### Claim 18 (depends on 12) The system of claim 12, wherein the plurality of wheels comprises a front wheel and a rear wheel, and the processor is further configured to: determine whether the wheel slip is present in the front wheel using the wheel speeds; determine whether the wheel slip is present in the rear wheel using the wheel speeds; and cause the regenerative braking system to provide regenerative braking torque for the vehicle: at a second level of the plurality of modulated levels if the wheel slip is present in the rear wheel but not in the front wheel; and at a third level of the plurality of modulated levels if the wheel slip is present in the rear wheel but not in the front wheel, the third level being less than the second level.