# US 7,613,558 B2 · Differential limiting control apparatus for a vehicle and the method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,613,558 B2 - Document ID: US7613558B2 - Status: Granted - Kind: B2 - Application number: 10/667,396 - Filed: 2003-09-23 - Published: 2004-03-25 - Granted: 2009-11-03 - Earliest claimed: 2002-09-24 - Assignees: Fuji Jukogyo Kabushiki Kaisha - Inventors: Takeshi Yoneda - Web page: https://patentgrep.com/patent/US7613558B2 ## CPC - B60K 23/0808: {for varying torque distribution between driven axles, e.g. by transfer clutch} - B60K 23/04: for differential gearing - F16D 48/06: Control by electric or electronic means, e.g. of fluid pressure - B60K 17/20: {in which the differential movement is limited} - B60T 2201/14: Electronic locking-differential - B60W 2050/001: {Proportional integral [PI] controller} - B60W 2050/0011: {Proportional Integral Differential [PID] controller} - B60W 2050/0012: {Feedforward or open loop systems} - B60W 2510/0604: Throttle position - B60W 2520/10: Longitudinal speed - B60W 2520/125: Lateral acceleration - B60W 2520/263: Slip values between front and rear axle - B60W 2520/28: Wheel speed - B60W 2530/20: Tyre data - B60W 2540/12: Brake pedal position - B60W 2710/025: Clutch slip, i.e. difference between input and output speeds - B60W 2710/027: Clutch torque - F16D 2500/10425: Differential clutch - F16D 2500/3021: Angle - F16D 2500/3101: Detection of a brake actuation by a sensor on the brake - F16D 2500/3109: Vehicle acceleration - F16D 2500/3115: Vehicle wheel speed - F16D 2500/5075: Prevention or regulation of vehicle's wheel slip - F16D 2500/50816: Control during a braking operation, e.g. during ABS control - F16D 2500/70252: Clutch torque - F16D 2500/70404: Force - F16D 2500/7044: Output shaft torque - F16D 2500/7061: Feed-back - F16D 2500/70631: Feed-forward - Y10T 74/1926: Speed responsive - B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES - 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 - 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 - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The differential limiting control apparatus having a clutch unit interposed between one rotational shaft and the other rotational shaft for variably transmitting a driving force between the one rotational shaft and the other rotational shaft, having: a feedback control unit for computing the clutch torque on basis of vehicle behaviors through a feedback control, a feed forward control unit for computing the clutch torque based on the behaviors through feed forward control, a tire diameter difference computing unit for computing a diameter difference of a tire, and a clutch torque computing unit for computing a final clutch torque by changing a ratio of the clutch torque obtained through the feedback control and a clutch torque obtained through the feed forward control so as to appropriately decide the feed forward control by effectively suppressing the tire slip while avoiding the occurrence of the internal circulation of the torque. ## Claims ### Claim 1 A differential limiting control apparatus for a vehicle having a clutch unit interposed between one rotational shaft and another rotational shaft for variably changing a driving force transmission between the one rotational shaft and the other rotational shaft, comprising: a target differential speed setting unit for setting a target differential speed between the one rotational shaft and the other rotational shaft, an actual differential speed detecting unit for detecting an actual differential speed between the one rotational shaft and the other rotational shaft, a first control unit for computing a first clutch torque of the clutch unit based on a deviation between the target differential speed and the actual differential speed, a throttle opening amount detecting unit for detecting a throttle opening amount, a second control unit for computing a second clutch torque of the clutch unit based on the throttle opening amount, a tire diameter difference computing unit for computing a diameter difference of a tire, and a final clutch torque computing unit for computing a final clutch torque wherein the final clutch torque computing unit computes the final clutch torque by a computation involving the first clutch torque, the second clutch torque, and at least one tire diameter difference ratio coefficient value which tire diameter difference ratio coefficient value changes according to the diameter difference of the tire so as to suppress a wheel slippage. ### Claim 2 (depends on 1) The differential limiting control apparatus as set forth in claim 1, wherein the first control unit comprises: a first clutch torque computing unit for computing the deviation between the target differential speed and the actual differential speed, and computing the first clutch torque by applying a sliding mode control with a switching function using at least a polarity related to an integral term of the deviation. ### Claim 3 (depends on 2) The differential limiting control apparatus as set forth in claim 2, wherein: the clutch unit is interposed between a front axle and a rear axle. ### Claim 4 (depends on 2) The differential limiting control apparatus as set forth in claim 2, wherein: the clutch unit limits a differential action of a differential interposed between a left wheel and a right wheel. ### Claim 5 (depends on 1) The differential limiting control apparatus as set forth in claim 1, wherein: the clutch unit is interposed between a front axle and a rear axle. ### Claim 6 (depends on 1) The differential limiting control apparatus as set forth in claim 1, wherein: the clutch unit limits a differential action of a differential interposed between a left wheel and a right wheel. ### Claim 7 (depends on 1) The differential limiting control apparatus as set forth in claim 1, further comprising a brake switch, and when an ON signal is inputted from the brake switch, the second clutch torque is made to be zero. ### Claim 8 (depends on 1) The differential limiting control apparatus as set forth in claim 1, wherein the final clutch torque (T lsd) involves the following equation: Tlsd=Rtr Tlsdff+(1−Rtr) Tlsdfb with Rtr representing the tire diameter difference ratio coefficient value based on the tire diameter difference; Tlsdff representing the second clutch torque; and Tlsdfb representing the first clutch torque. ### Claim 9 (depends on 8) The differential limiting control apparatus as set forth in claim 8, wherein the Rtr decreases as the diameter difference of the tire increases. ### Claim 10 (depends on 8) The differential limiting control apparatus as set forth in claim 8, wherein the Rtr is 0.5 in the case where the diameter difference of the tire is substantially zero. ### Claim 11 (depends on 1) The differential limiting control apparatus as set forth in claim 1, wherein said computing unit utilizes a first contribution value and a second contributing value and wherein each of said first and second contributing values involves said at least one tire diameter difference ratio coefficient value, and wherein said first contributing value associated with the first clutch torque in the computation of the final clutch torque increases as the diameter difference of the tire increases and said second contributing value associated with the second clutch toque in the computation of the final clutch torque decreases as the diameter difference of the tire increases, and the first contributing value associated with the first clutch torque decreases and the second contributing value associated with the second clutch torque increases as the diameter difference of the tire decreases. ### Claim 12 (depends on 1) The differential limiting control apparatus as set forth in claim 1, wherein said at least one tire diameter difference ratio coefficient value comprises a first tire diameter difference ratio coefficient value and a second tire diameter difference ratio coefficient value, and wherein said final clutch torque computing unit computes the final clutch torque by a computation comprising said first tire diameter difference ratio coefficient value and said second tire diameter difference ratio coefficient value, wherein said first tire diameter difference ratio coefficient value is in association with one of said first and second clutch torques, and wherein said second tire diameter difference ratio coefficient value is in association with an opposite one of said first and second clutch torques, and wherein the final clutch torque computing unit reduces the one of said first and second tire diameter difference ratio coefficient values that is associated with said second clutch torque and increases the opposite one of said first and second ratio coefficient values that is associated with said first clutch torque as the diameter difference of the tire increases. ### Claim 13 (depends on 12) The differential limiting control apparatus as set forth in claim 12, wherein: the clutch unit is interposed between a front axle and a rear axle. ### Claim 14 (depends on 12) The differential limiting control apparatus as set forth in claim 12, wherein: the clutch unit limits a differential action of a differential interposed between a left wheel and a right wheel. ### Claim 15 (depends on 12) The differential limiting control apparatus as set forth in claim 12, wherein said final clutch torque computing unit computes the final clutch torque with a summation involving a first multiplication comprising said first clutch torque and said second tire diameter difference ratio coefficient value and a second multiplication comprising said second clutch torque and said first tire diameter difference ratio coefficient value. ### Claim 16 A differential limiting control apparatus for a vehicle having a clutch unit interposed between one rotational shaft and another rotational shaft for variably changing a driving force transmission between the one rotational shaft and the other rotational shaft, comprising: a target differential speed setting unit for setting a target differential speed between the one rotational shaft and the other rotational shaft, an actual differential speed detecting unit for detecting an actual differential speed between the one rotational shaft and the other rotational shaft, a first control unit for computing a first clutch torque of the clutch unit based on a deviation between the target differential speed and the actual differential speed, a throttle opening amount detecting unit for detecting a throttle opening amount, a second control unit for computing a second clutch torque of the clutch unit based on the throttle opening amount, a tire diameter difference computing unit for computing a diameter difference of a tire and outputting a tire diameter difference value, and a final clutch torque computing unit for computing a final clutch torque wherein the final clutch torque computing unit receives, as an input, said tire diameter difference value and computes the final clutch torque by a computation involving the first clutch torque and the second clutch torque, and which computation includes a ratio coefficient value which ratio coefficient value changes according to the diameter difference of the tire so as to vary the final clutch torque to promote wheel slippage suppression. ### Claim 17 A differential limiting control apparatus for a vehicle having a clutch unit interposed between one rotational shaft and another rotational shaft for variably changing a driving force transmission between the one rotational shaft and the other rotational shaft, comprising: a target differential speed setting unit for setting a target differential speed between the one rotational shaft and the other rotational shaft, an actual differential speed detecting unit for detecting an actual differential speed between the one rotational shaft and the other rotational shaft, a first control unit for computing a first clutch torque of the clutch unit based on vehicle behavior through a feedback control, a second control unit for computing a second clutch torque of the clutch unit based on behavior of the vehicle through a feed forward control, a tire diameter difference computing unit for computing a diameter difference of a tire and outputting a tire diameter difference value, and a final clutch torque computing unit for computing a final clutch torque wherein the final clutch torque computing unit receives, as an input, said tire diameter difference value and computes the final clutch torque by a computation involving (i) the first clutch torque and a first weighting value associated with said tire diameter difference value and (ii) and the second clutch torque and a second weighting value associated with said tire diameter difference value, and wherein said first and second weighting values vary in opposite fashion upon a change in the tire diameter value.