Control device for work machine, and work machine

Abstract

To provide a control device of a working machine capable of increasing means for recovering regenerative electric power.SOLUTION: A work machine (10) includes at least one first motor generator (13,23) that performs driving and power generation, at least one driven unit (11,21) that is driven by the first motor generator, at least one second motor generator (42,52) that performs driving and power generation, and at least one work mechanism (41,51) that is driven by the second motor generator and performs work while changing a height. A control device (35) controls operations of the first motor generator and the second motor generator, and when causing the first motor generator to perform regenerative power generation by kinetic energy of the driven part, causes the second motor generator to be driven by regenerative power generated by the regenerative power generation to perform a regenerative operation of raising the work mechanism higher than a current height.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for controlling a work machine. [Background technology]

[0002] For example, there is a construction machine that includes an AC motor that drives a rotating body and a capacitor that supplies power to the AC motor and charges it with power regenerated from the AC motor, and that estimates the next operation of the rotating body, calculates the amount of power to be regenerated from the AC motor based on the estimated next operation, and sets a target voltage for the capacitor based on the calculated amount of power (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-82644 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the construction machine (an example of a work machine) described in Patent Document 1 requires an electricity storage device such as a capacitor or battery to recover regenerative power, and there is still room for improvement.

[0005] The present invention has been made to solve the above-mentioned problems, and a main object of the present invention is to provide a control device for a work machine that can increase the means for recovering regenerative power. [Means for solving the problem]

[0006] The first means for solving the above problem is: at least one first motor generator (13, 23) for driving and generating electricity; at least one driven part (11, 21) driven by the first motor generator; at least one second motor generator (42, 52) for driving and generating electricity; at least one working mechanism (41, 51, 151) driven by the second motor generator and working while changing height; A control device (35) adapted to a work machine (10, 110) including the first motor-generator and the second motor-generator, the control device controlling the operation of the first motor-generator and the second motor-generator, When the control device causes the first motor generator to generate power regeneratively using the kinetic energy of the driven part, the control device drives the second motor generator using the regenerative power generated by the power regeneration, thereby performing a regenerative operation to raise the working mechanism above its current height.

[0007] According to the above configuration, at least one driven part is driven by at least one first motor-generator and has kinetic energy. When the movement of the driven part is stopped, the first motor-generator can generate regenerative power using the kinetic energy of the driven part. At least one working mechanism is driven by at least one second motor-generator and works while changing its height. A control device controls the operation of the first motor-generator and the second motor-generator.

[0008] Here, the higher the height of the working mechanism, the greater the potential energy possessed by the working mechanism. In this regard, when the control device causes the first motor-generator to generate regenerative power using the kinetic energy of the driven parts, the control device drives the second motor-generator with the regenerative power generated by the regenerative power generation, thereby performing a regenerative operation to raise the working mechanism above its current height. As a result, the regenerative power generated by the regenerative power generation of the first motor-generator can be converted into potential energy of the working mechanism and recovered. Therefore, the control device for the working machine can add means for recovering regenerative power other than the power storage device. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a block diagram showing a configuration of a power shovel and a flow of energy according to a first embodiment. [Figure 2] 4 is a flowchart showing an operation procedure during regenerative power generation of the power shovel. [Figure 3] FIG. 4 is a side view showing the angles of the boom and arm during regenerative operation of the power shovel. [Figure 4] FIG. 2 is a block diagram showing the flow of energy during regenerative power generation. [Figure 5] FIG. 6 is a block diagram showing the configuration and energy flow of a wheel loader according to a second embodiment. [Figure 6] 4 is a flowchart showing an operation procedure during regenerative power generation of the wheel loader. [Figure 7] FIG. 10 is a side view showing the angles of the boom and bucket during regenerative operation of the wheel loader. [Figure 8] FIG. 10 is a block diagram showing the configuration and energy flow of a modified example of the power shovel. [Figure 9] 10 is a flowchart showing an operation procedure during regenerative power generation in a modified example of the power shovel. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) Hereinafter, a first embodiment embodied in a control device applied to a power shovel (an example of a work machine) will be described with reference to the drawings.

[0011] As shown in Fig. 1, the power shovel 10 includes a traveling mechanism 11, a brake 12, a traveling MG (Motor Generator) 13, a swing mechanism 21, a brake 22, a swing MG 23, a power control unit 30, a boom 41, a boom MG 42, an arm 51, an arm MG 52, an operation unit 60, a battery 70, and accessories 80. In Fig. 1, solid arrows indicate the flow of energy, and dashed arrows indicate the transmission and reception of signals.

[0012] The battery 70 (corresponding to a power storage device) is a secondary battery such as a lithium ion battery, and supplies DC power to the first INV (inverter) unit 31. The battery 70 is charged by the power supplied from the first INV unit 31.

[0013] The first INV unit 31 includes INVs 32 and 33. The INVs 32 and 33 convert DC power supplied from the battery 70 into AC power and supply it to the traveling MG 13 and the swinging MG 23, respectively. The INVs 32 and 33 also convert AC power supplied from the traveling MG 13 and the swinging MG 23, respectively, into DC power and supply it to the battery 70. The INV 32 also converts AC power supplied from the traveling MG 13 into AC power of a different voltage, for example, and supplies it to the second INV unit 36. The INV 33 also converts AC power supplied from the swinging MG 23 into AC power of a different voltage, for example, and supplies it to the second INV unit 36. The INV 32 also converts AC power supplied from the second INV unit 36 ​​into AC power of a different voltage, for example, and supplies it to the traveling MG 13. The INV 33 also converts AC power supplied from the second INV unit 36 ​​into AC power of a different voltage, for example, and supplies it to the swinging MG 23. The INVs 32 and 33 are controlled by an ECU (Electronic Control Unit) 35 .

[0014] The travel MG 13 (corresponding to a first motor generator) is an AC motor such as a three-phase AC motor, and drives the travel mechanism 11 with AC power supplied from the INV 32. The travel MG 13 also generates electric power regeneratively using the kinetic energy of the travel mechanism 11, and supplies the AC power generated by the regenerative power generation to the INV 32. The battery 70 stores the electric power regenerated by the travel MG 13 and converted by the INV 32.

[0015] The traveling mechanism 11 (corresponding to the driven part) is driven by the traveling MG 13 to travel the power shovel 10. As a result, the traveling mechanism 11, i.e., the power shovel 10, enters a state of having kinetic energy. Furthermore, the traveling mechanism 11 rotates the rotor of the traveling MG 13 using its own kinetic energy, causing the traveling MG 13 to generate regenerative power.

[0016] The brake 12 is, for example, an electromagnetic brake that is actuated to brake the traveling mechanism 11. The brake 12 converts the kinetic energy of the traveling mechanism 11 into heat and consumes the heat. The brake 12 is actuated by power supplied from the battery 70. The actuation state of the brake 12 is controlled based on operation of a brake pedal (an example of a brake operation member) by the operator of the power shovel 10 and commands from the ECU 35. The brake 12 may also be a hydraulically actuated brake that is actuated by hydraulic pressure supplied from an electric pump. In this case, the drive state of the electric pump is controlled based on operation of the brake pedal by the operator of the power shovel 10 and commands from the ECU 35.

[0017] The swing MG 23 (corresponding to a first motor generator) is an AC motor such as a three-phase AC motor, and drives the swing mechanism 21 with AC power supplied from the INV 33. The swing MG 23 also generates electric power regeneratively using the kinetic energy of the swing mechanism 21, and supplies the regenerated AC power to the INV 33. The battery 70 stores the electric power regenerated by the swing MG 23 and converted by the INV 33.

[0018] The swivel mechanism 21 (corresponding to the driven part) is driven by the swivel MG 23 and swivels relative to the traveling mechanism 11. A boom 41 is attached to the swivel mechanism 21, and an arm 51 is attached to the boom 41. When the swivel mechanism 21 swivels, the boom 41 and the arm 51 swivel integrally with the swivel mechanism 21. As a result, the swivel mechanism 21, i.e., the boom 41 and the arm 51, enter a state in which they possess kinetic energy. Furthermore, the swivel mechanism 21 uses its own kinetic energy to rotate the rotor of the swivel MG 23, causing the swivel MG 23 to generate regenerative power.

[0019] The brake 22 is, for example, a non-excitation operation type (excitation release type) electromagnetic brake, and brakes the swing mechanism 21. The brake 22 converts the kinetic energy of the swing mechanism 21 into heat and consumes it. The brake 22 operates to brake the swing mechanism 21 when power is not supplied from the battery 70, and is deactivated to release the swing mechanism 21 when power is supplied from the battery 70. After the operator starts the power shovel 10 (i.e., while the power shovel 10 is in operation), the brake 22 is excited (operated), and the swing mechanism 21 is released. The operating state of the brake 22 is controlled based on commands from the ECU 35.

[0020] The auxiliary equipment 80 (corresponding to an electric auxiliary equipment) includes, for example, an air conditioner and a headlight. The auxiliary equipment 80 operates on power supplied from the battery 70. The auxiliary equipment 80 also operates on power supplied via the second INV unit 36.

[0021] The second INV unit 36 ​​includes INVs 37 and 38. The INVs 37 and 38 convert the AC power supplied from the first INV unit 31 into DC power and supply it to the auxiliary equipment 80. The INV 37 also converts the AC power supplied from the first INV unit 31 into AC power of a different voltage, for example, and supplies it to the boom MG 42. The INV 38 converts the AC power supplied from the first INV unit 31 into AC power of a different voltage, for example, and supplies it to the arm MG 52. The INVs 37 and 38 also convert the AC power supplied from the boom MG 42 and the arm MG 52 into DC power and supply it to the auxiliary equipment 80. The INV 37 also converts the AC power supplied from the boom MG 42 into AC power of a different voltage, for example, and supplies it to the first INV unit 31. The INV 38 converts the AC power supplied from the arm MG 52 into AC power of a different voltage, for example, and supplies it to the first INV unit 31. The INVs 32 and 33 are controlled by an ECU (Electronic Control Unit) 35 .

[0022] The boom MG42 (corresponding to a second motor generator) is an AC motor such as a three-phase AC motor, and drives the boom 41 with AC power supplied from the INV 37. The boom MG42 also generates power regeneratively using the potential energy of the boom 41, and supplies the AC power generated by the regenerative power generation to the INV 37.

[0023] The boom 41 (corresponding to the working mechanism) is attached to the swivel mechanism 21 and rotates integrally with the swivel mechanism 21. The boom 41 is driven by the boom MG42 and swings up and down around a fulcrum. That is, the boom 41 works while changing its height, and its own potential energy changes depending on the height. The boom 41 also rotates the rotor of the boom MG42 using its own potential energy, causing the boom MG42 to generate regenerative power.

[0024] The arm MG52 (corresponding to a second motor generator) is an AC motor such as a three-phase AC motor, and drives the arm 51 with AC power supplied from the INV 38. The arm MG52 also generates power regeneratively using the potential energy of the arm 51, and supplies the AC power generated by the regenerative power generation to the INV 38.

[0025] The arm 51 (corresponding to the working mechanism) is attached to the tip of the boom 41. That is, the arm 51 is attached to the swivel mechanism 21 via the boom 41, and swivels integrally with the boom 41 and the swivel mechanism 21. The arm 51 is driven by the arm MG52 and swings up and down around a fulcrum. That is, the arm 51 works while changing its height, and its own potential energy changes depending on the height. The arm 51 also rotates the rotor of the arm MG52 using its own potential energy, causing the arm MG52 to generate regenerative power.

[0026] The operating unit 60 is operated by the operator of the power shovel 10, and causes the boom 41 and the arm 51 to perform work in accordance with the operation. The operator operates an accelerator pedal, a brake pedal, and other operating levers (not shown) to operate the traveling mechanism 11, the brake 12, and the swing mechanism 21.

[0027] The ECU 35 (corresponding to a control device) is mainly composed of a microcomputer including, for example, a CPU, ROM, RAM, and an input / output interface. The ECU 35 inputs commands to the INVs 32 and 33 to control them. This controls the power input / output between the INVs 32 and 33 and the travel MG 13 and the swing MG 23, respectively, the power input / output between the INVs 32 and 33 and the battery 70, and the power input / output between the INVs 32 and 33 and the second INV unit 36. That is, the ECU 35 controls the operation of the travel MG 13 and the swing MG 23 via the first INV unit 31. The ECU 35 also inputs commands to the INVs 37 and 38 to control them. This controls the power input / output between the INVs 37 and 38 and the boom MG 42 and the arm MG 52, respectively, the power input from the INVs 37 and 38 to the accessory 80, and the power input / output between the INVs 37 and 38 and the first INV unit 31. That is, ECU 35 controls the operation of boom MG 42 and arm MG 52 via second INV unit 36. ECU 35 inputs commands to INVs 32, 33, 37, and 38 based on operation signals that indicate the operating states of operation unit 60, accelerator pedal, brake pedal, other control levers, etc. ECU 35 and INVs 32, 33, 37, and 38 form a power control unit 30 that controls the input and output of power between each device.

[0028] 2 is a flowchart showing the operation procedure during regenerative power generation of the power shovel 10. This series of processes is executed by the ECU 35 when the operator stops the operation of rotating the swing mechanism 21. Here, an example will be described in which the swing MG 23 is caused to generate regenerative power using the kinetic energy of the swing mechanism 21.

[0029] First, it is determined whether or not it has been detected that the swing mechanism 21 is swinging (S10). For example, it is detected that the swing mechanism 21 is swinging based on the detection result of a rotation speed sensor that detects the rotation speed of the swing MG 23, whether or not power is being supplied to the swing MG 23, etc. In this determination, if it is determined that it has not been detected that the swing mechanism 21 is swinging (S10: NO), this series of processes is temporarily ended (END).

[0030] On the other hand, if it is determined in step S10 that the rotation mechanism 21 is rotating (S10: YES), the regenerative energy E generated until the rotation is stopped is calculated (S11). For example, kinetic energy is calculated as the regenerative energy E based on the rotation speed of the rotation mechanism 21 and the moments of inertia of the rotation mechanism 21, the boom 41, and the arm 51. This method of calculating kinetic energy is described in, for example, Patent Document 1, and therefore a detailed description thereof will be omitted.

[0031] Next, it is determined whether the regenerative energy E>the chargeable energy Eb and whether there is no request to prohibit lifting of the boom 41 and the arm 51 (S12). The chargeable energy Eb is the electrical energy that can be stored in the battery 70 from its current charge state until it reaches a fully charged state. Furthermore, for example, if the operator operates the control unit 60 to move the boom 41 and the arm 51, it is determined that there is a request to prohibit lifting of the boom 41 and the arm 51. If the operator does not operate the control unit 60, it is determined that there is no request to prohibit lifting of the boom 41 and the arm 51. If the determination in S12 is negative (S12: NO), regenerative power is generated by the swing MG 23, and the battery 70 is charged with the regenerative power generated by the regenerative power generation (S13). If the operator starts to rotate the traveling mechanism 11 during regenerative power generation, the regenerative power generation is stopped and this series of processes is temporarily terminated. After the process in S13, the process is executed again from S10.

[0032] On the other hand, if the determination in S12 is affirmative (S12: YES), regenerative power is generated by the swing MG 23, and the battery 70 is charged to a fully charged state with the regenerative power generated by the regenerative power generation (S14). Note that if the operator starts an operation to swing the traveling mechanism 11 during regenerative power generation, or if the operator starts an operation on the operation unit 60, regenerative power generation is stopped and this series of processes is temporarily terminated.

[0033] Next, a lifting angle α of the boom 41 necessary to recover the regenerated energy E is calculated (S15). More specifically, as shown in FIG. 3, the lifting angle α is calculated so that when the boom 41 is lifted from the current lifting angle αn of the boom 41 to the lifting angle α, all of the remaining regenerated energy E after the battery 70 is fully charged is converted into potential energy of the boom 41 and the arm 51. The current lifting angle αn is detected by a resolver attached to the boom MG 42, an angle sensor attached to the boom 41, or the like. The relationship between the regenerated energy E, the current lifting angle αn, and the lifting angle α necessary to convert it into potential energy can be obtained in advance by testing or the like and specified in a table or map. The lifting angle α can then be calculated by applying the regenerated energy E and the current lifting angle αn to the table or map. A maximum lifting angle αmax, which is the maximum angle at which the boom 41 can be lifted, is set for the boom 41. The height of the boom 41 when the lifting angle of the boom 41 is the lifting angle α, corresponds to the target height of the boom 41. The height of the boom 41 when the lifting angle of the boom 41 is the maximum lifting angle αmax corresponds to the upper limit height of the boom 41.

[0034] Next, it is determined whether the lifting angle α is greater than the maximum lifting angle αmax (S16). If it is determined that the lifting angle α is not greater than the maximum lifting angle αmax (S16: NO), regenerative power is generated by the swing MG 23, and the boom MG 42 is driven by the regenerative power generated by the regenerative power generation to lift the boom 41 to the lifting angle α (S17). Note that if the operator starts an operation to swing the traveling mechanism 11 while the boom 41 is being lifted, or if the operator starts operating the operation unit 60, the regenerative power generation and lifting of the boom 41 are stopped, and this series of processes is temporarily terminated. After the process of S17, the process is executed again from S10.

[0035] On the other hand, if it is determined in S16 that the lifting angle α is greater than the maximum lifting angle αmax (S16: YES), the boom 41 is lifted to the maximum lifting angle αmax using the regenerative power generated by the regenerative power generation (S18). Also, the energy Eα required to lift the boom 41 from the current lifting angle αn to the maximum lifting angle αmax is calculated. Note that if the operator starts an operation to rotate the traveling mechanism 11 while the boom 41 is being lifted, or if the operator starts operating the operation unit 60, the regenerative power generation and lifting of the boom 41 are stopped or stopped, and this series of processes is temporarily terminated.

[0036] Next, a lifting angle β of the arm 51 necessary to recover the regenerative energy E is calculated (S19). More specifically, as shown in FIG. 3, the lifting angle β is calculated so that when the arm 51 is lifted from the current lifting angle βn of the arm 51 to the lifting angle β, all of the remaining regenerative energy E after the boom 41 is lifted to the maximum lifting angle αmax is converted into potential energy of the arm 51. The current lifting angle βn is detected by a resolver attached to the arm MG52, an angle sensor attached to the arm 51, or the like. The relationship between the regenerative energy E, the current lifting angle βn, and the lifting angle β necessary to convert it into potential energy can be obtained in advance by testing or the like and specified in a table or map. The lifting angle β can then be calculated by applying the regenerative energy E and the current lifting angle βn to the table or map. A maximum lifting angle βmax, which is the maximum angle at which the arm 51 can be lifted, is set for the arm 51. The height of the arm 51 when the lifting angle of the arm 51 is the lifting angle β, corresponds to the target height of the arm 51. The height of the arm 51 when the lifting angle of the arm 51 is the maximum lifting angle βmax corresponds to the upper limit height of the arm 51.

[0037] Next, it is determined whether the lift angle β is greater than the maximum lift angle βmax (S20). If it is determined that the lift angle β is not greater than the maximum lift angle βmax (S20: NO), regenerative power is generated by the swing MG 23, and the arm MG 52 is driven by the regenerative power generated by the regenerative power generation to lift the arm 51 to the lift angle β (S21). Note that if the operator starts an operation to swing the traveling mechanism 11 while the arm 51 is being lifted, or if the operator starts operating the operation unit 60, the regenerative power generation and lifting of the arm 51 are stopped, and this series of processes is temporarily terminated. After the process of S21, the process is executed again from S10.

[0038] On the other hand, if it is determined in S20 that the lifting angle β is greater than the maximum lifting angle βmax (S20: YES), the arm 51 is lifted to the maximum lifting angle βmax using the regenerative power generated by regenerative power generation (S22). The energy Eβ required to lift the arm 51 from the current lifting angle βn to the maximum lifting angle βmax is calculated. If the operator starts to rotate the traveling mechanism 11 while the arm 51 is being lifted, or if the operator starts to operate the operating unit 60, the regenerative power generation and lifting of the arm 51 are stopped, and this series of processes is temporarily terminated.

[0039] Next, all of the accessories 80 are driven for a predetermined time (S23). Specifically, the air conditioner and headlights are driven for a predetermined time as all of the accessories 80 provided in the power shovel 10. The predetermined time is as short as possible for consuming the remaining regenerative energy E after the arm 51 has been lifted up to the maximum lifting angle βmax, and is, for example, 5 seconds. In addition, the energy Eγ required to drive all of the accessories 80 for the predetermined time is calculated.

[0040] Next, it is determined whether the energy obtained by subtracting the energies Eα, Eβ, and Eγ from the regenerative energy E at the start of regenerative power generation is equal to or less than 0 (S24). If it is determined that E-Eα-Eβ-Eγ≦0 (S24: YES), this series of processes is terminated (END). On the other hand, if it is determined that E-Eα-Eβ-Eγ≦0 is not satisfied (S24: NO), the brake 22 is activated (S25). Because the brake 22 is a non-excitation-operated brake, excitation of the brake 22 is stopped, and the turning mechanism 21 is braked by the brake 22. Then, the process is executed again from S10.

[0041] 4 is a block diagram showing the flow of energy during regenerative power generation. Here, an example will be described in which the kinetic energy of the swing mechanism 21 is used to cause the swing MG 23 to generate regenerative power.

[0042] When the operator stops the operation of rotating the swing mechanism 21 while operating the swing mechanism 21, regenerative power generation by the swing MG 23 starts. The regenerative power generated by the regenerative power generation is charged into the battery 70 via the first INV unit 31. If the kinetic energy of the swing mechanism 21 becomes zero before the battery 70 becomes fully charged, the regenerative power generation ends. If the kinetic energy of the swing mechanism 21 does not become zero, the battery 70 is charged until it becomes fully charged.

[0043] When the battery 70 is fully charged, the regenerative power is supplied to the boom MG 42 via the first INV unit 31 and the second INV unit 36, and the boom 41 is lifted. If the kinetic energy of the swivel mechanism 21 becomes zero before the lifting angle of the boom 41 reaches the maximum lifting angle αmax, lifting of the boom 41 is terminated. If the kinetic energy of the swivel mechanism 21 does not become zero, the boom 41 is lifted until the lifting angle of the boom 41 reaches the maximum lifting angle αmax.

[0044] When the lifting angle of the boom 41 reaches the maximum lifting angle αmax, the regenerative power is supplied to the arm MG52 via the first INV unit 31 and the second INV unit 36, and the arm 51 is lifted. If the kinetic energy of the rotation mechanism 21 becomes 0 before the lifting angle of the arm 51 reaches the maximum lifting angle βmax, the lifting of the arm 51 is terminated. If the kinetic energy of the rotation mechanism 21 does not become 0, the arm 51 is lifted until the lifting angle of the arm 51 reaches the maximum lifting angle βmax.

[0045] When the lifting angle of the arm 51 reaches the maximum lifting angle βmax, the regenerative power is supplied to the auxiliary device 80 via the first INV unit 31 and the second INV unit 36, and the auxiliary device 80 is driven until a predetermined time has elapsed. If the kinetic energy of the swing mechanism 21 becomes zero after the auxiliary device 80 has been driven for the predetermined time, regenerative power generation is terminated. If the kinetic energy of the swing mechanism 21 does not become zero after the auxiliary device 80 has been driven for the predetermined time, the swing mechanism 21 is braked by the brake 22.

[0046] When utilizing the potential energy of the boom 41 and the arm 51 after the rotation of the rotation mechanism 21 and the regenerative power generation by the rotation MG 23 have finished, the ECU 35 performs control, for example, as follows: That is, the ECU 35 lowers the boom 41 and the arm 51 from their current heights, thereby causing the boom MG 42 and the arm MG 52 to generate regenerative power using the potential energy of the boom 41 and the arm 51. The ECU 35 drives the auxiliary equipment 80, the traveling MG 13, and the rotation MG 23 using the regenerative power generated by the regenerative power generation.

[0047] The present embodiment described above in detail has the following advantages.

[0048] The higher the height of the boom 41 and the arm 51, the greater the potential energy possessed by the boom 41 and the arm 51. In this regard, when the ECU 35 causes the swing MG 23 to generate regenerative power using the kinetic energy of the swing mechanism 21, the ECU 35 drives the boom MG 42 and the arm MG 52 with the regenerative power generated by the regenerative power generation, thereby performing a regenerative operation to raise the boom 41 and the arm 51 above their current heights. Therefore, the regenerative power generated by the regenerative power generation of the swing MG 23 can be converted into potential energy of the boom 41 and the arm 51 and recovered. Therefore, the ECU 35 of the power shovel 10 can add means for recovering regenerative power other than the battery 70.

[0049] The ECU 35 prohibits regenerative operation when the operator operates the operation unit 60 and the boom 41 and the arm 51 are working. With this configuration, when the operator operates the operation unit 60 to cause the boom 41 and the arm 51 to work, it is possible to prohibit regenerative operation that would use regenerative power generated by regenerative power generation to raise the boom 41 and the arm 51 above their current height. This makes it possible to prevent the boom 41 and the arm 51 from performing an operation different from the operation performed by the operator.

[0050] The ECU 35 calculates the lifting angles α and β (target heights) of the boom 41 and the arm 51 required to convert the kinetic energy of the swing mechanism 21 into potential energy of the boom 41 and the arm 51 through regenerative operation, and raises the boom 41 and the arm 51 to the lifting angles α and β, respectively. With this configuration, by raising the boom 41 and the arm 51 through regenerative operation to the lifting angles α and β, respectively, the kinetic energy of the swing mechanism 21 can be converted into potential energy of the boom 41 and the arm 51 and recovered. Furthermore, the lifting angles α and β can be easily calculated using a table or map obtained in advance.

[0051] When the angle at which the boom 41 and the arm 51 can be lifted (the height at which they can be raised) is limited to or below the maximum lifting angles αmax, βmax (upper limit height), the target lifting angles α, β of the boom 41 and the arm 51 may exceed the maximum lifting angles αmax, βmax. In this regard, the ECU 35 terminates the regenerative operation when the lifting angles of the boom 41 and the arm 51 reach the maximum lifting angles αmax, βmax (when they have been lifted up to the maximum lifting angles αmax, βmax). With this configuration, it is possible to prevent the boom 41 and the arm 51 from being lifted beyond the maximum lifting angles αmax, βmax during the regenerative operation. Therefore, it is possible to prevent damage to the boom 41 and the arm 51.

[0052] When the ECU 35 determines that the battery 70 can store the regenerated power generated by the regenerative power generation, the ECU 35 stores the regenerated power in the battery 70. This allows the battery 70 to recover the regenerated power preferentially, making it easier to use the recovered regenerated power. On the other hand, when the ECU 35 determines that the battery 70 cannot store the regenerated power, for example, when the battery 70 is fully charged, the ECU 35 executes a regenerative operation (S17, S21) to recover the regenerated power. This increases the reusability of the recovered regenerated power while increasing the number of means for recovering the regenerated power.

[0053] During the regenerative operation, the boom 41 and the arm 51 (multiple working mechanisms) are raised from their current height, so that the number of means for recovering regenerative power can be further increased, and the amount of regenerative power recovered can be increased.

[0054] When the ECU 35 causes the swing MG 23 to generate regenerative power using the kinetic energy of the swing mechanism 21, the ECU 35 sequentially raises the boom 41 and the arm 51 from their current heights in accordance with a preset priority order. This makes it possible to prevent the boom 41 and the arm 51 from operating in an inappropriate order.

[0055] Specifically, when the boom 41 and the arm 51 are raised above their current heights, the boom 41 is raised above its current height and then the arm 51 is raised above that height. More specifically, the boom 41 is raised to the maximum lifting angle αmax, and then the arm 51 is raised. For this reason, raising the boom 41 first makes it easier to ensure the operator's field of vision, and raising the arm 51 after the boom 41 can prevent the arm 51 from colliding with the surroundings.

[0056] When the lifting angles of the boom 41 and the arm 51 (all working mechanisms) reach their maximum lifting angles αmax and βmax due to the regenerative operation, the regenerative power generated by the regenerative power generation of the swing MG 23 cannot be converted into potential energy of the boom 41 and the arm 51 and recovered. In this regard, when the lifting angles of the boom 41 and the arm 51 reach their maximum lifting angles αmax and βmax due to the regenerative operation and the swing MG 23 is caused to generate regenerative power using the kinetic energy of the swing mechanism 21, the ECU 35 drives the auxiliary machine 80 with the regenerative power generated by the regenerative power generation. Therefore, even when the recovery of regenerative power through the regenerative operation has reached its limit, the regenerative power generated by the regenerative power generation can be effectively used to drive the auxiliary machine 80.

[0057] Even after the recovery of regenerative power through regenerative operation has reached its limit and all accessories 80 have been driven for a predetermined time, the swing mechanism 21 may still have kinetic energy to consume. In this regard, the ECU 35 activates the brake 22 when the lift angles of the boom 41 and arm 51 (all working mechanisms) have reached their maximum lift angles αmax and βmax, respectively, through regenerative operation, all accessories 80 have been driven for a predetermined time, and the swing mechanism 21 still has kinetic energy to consume. Therefore, when the kinetic energy of the swing mechanism 21 cannot be fully recovered through regenerative operation and driving of accessories 80, the brake 22 can convert the kinetic energy into heat and consume it. This prevents excessive regenerative power generation and prevents damage to the boom 41 and arm 51. It also prevents damage to the battery 70 due to excessive power storage.

[0058] The ECU 35 lowers the boom 41 and the arm 51 from their current heights, thereby causing the boom MG42 and the arm MG52 to generate regenerative power using the potential energy of the boom 41 and the arm 51. With this configuration, the kinetic energy of the swing mechanism 21, which is converted into potential energy of the boom 41 and the arm 51 and then recovered, can be converted into regenerative power by the regenerative power generation of the boom MG42 and the arm MG52 and used.

[0059] (Second embodiment) A second embodiment in which the power shovel 10 of the first embodiment is changed to a wheel loader will be described below with reference to Figs. 5 to 7. As shown in Figs. 5 and 7, the wheel loader 110 has a bucket 151 and a bucket MG152 instead of the arm 51 and arm MG52 of the power shovel 10. The wheel loader 110 does not have a swing mechanism 21, a brake 22, a swing MG 23, or an INV 33. The other configuration of the wheel loader 110 is similar to that of the power shovel 10. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be incorporated herein.

[0060] FIG. 6 is a flowchart showing the operational procedure during regenerative power generation of the wheel loader 110. The same processing as in the flowchart of FIG. 2 is given the same step number S, and the description thereof is incorporated herein. Here, an example will be described in which the traveling MG 13 is caused to generate regenerative power using the kinetic energy of the traveling mechanism 11. For this reason, with respect to the description of FIG. 2 already given, "swing mechanism 21" will be read as "traveling mechanism 11," "brake 22" will be read as "brake 12," "swing MG 23" will be read as "traveling MG 13," "swing" will be read as "traveling," and "arm 51" will be read as "bucket 151." This series of processing is executed by the ECU 35 when the operator has stopped operating the wheel loader 110 to travel.

[0061] First, it is determined whether or not it has been detected that the traveling mechanism 11 is decelerating naturally (S10A). For example, it is determined whether or not the accelerator pedal (accelerator operating member) of the wheel loader 110 is not being depressed (operated), the brake pedal (brake operating member) is not being depressed (operated), and the speed of the wheel loader 110 is decreasing. In this determination, if it is determined that it has not been detected that the traveling mechanism 11 is decelerating naturally (S10A: NO), this series of processes is temporarily ended (END). On the other hand, in this determination, if it is determined that it has been detected that the traveling mechanism 11 is decelerating naturally (S10A: YES), the process of S11 is executed.

[0062] The processing of S11 to S18 is the same as the processing of S11 to S18 in FIG. 2 with the above-mentioned replacement.

[0063] In the processing of S19A, a lifting angle β of the bucket 151 necessary to recover the regenerative energy E is calculated (S19A). More specifically, as shown in FIG. 7, the lifting angle β is calculated so that when the bucket 151 is lifted from the current lifting angle βn of the bucket 151 to the lifting angle β, all of the remaining regenerative energy E after the boom 41 has been lifted to the maximum lifting angle αmax is converted into potential energy of the bucket 151. A maximum lifting angle βmax, which is the maximum angle at which the bucket 151 can be lifted, is set for the bucket 151. The height of the bucket 151 when the lifting angle of the bucket 151 is the lifting angle β, corresponds to the target height of the bucket 151. The height of the bucket 151 when the lifting angle of the bucket 151 is the maximum lifting angle βmax corresponds to the upper limit height of the bucket 151.

[0064] Next, it is determined whether the lift angle β is greater than the maximum lift angle βmax (S20). If it is determined that the lift angle β is not greater than the maximum lift angle βmax (S20: NO), regenerative power is generated by the traveling MG 13, and the bucket MG 152 is driven by the regenerative power generated to lift the bucket 151 to the lift angle β (S21A). Note that if the operator starts an operation to cause the traveling mechanism 11 to travel while the bucket 151 is being lifted, or if the operator starts operating the operating unit 60, regenerative power generation and lifting of the bucket 151 are stopped, and this series of processes is temporarily terminated. After the process of S21A, the process is executed again from S10A.

[0065] On the other hand, if it is determined in S20 that the lifting angle β is greater than the maximum lifting angle βmax (S20: YES), the bucket 151 is lifted to the maximum lifting angle βmax using the regenerative power generated by regenerative power generation (S22A). The energy Eβ required to lift the bucket 151 from the current lifting angle βn to the maximum lifting angle βmax is calculated. If the operator starts operating the traveling mechanism 11 to travel while the bucket 151 is being lifted, or if the operator starts operating the operating unit 60, the regenerative power generation and lifting of the bucket 151 are stopped, and this series of processes is temporarily terminated.

[0066] The processes of S23 and S24 are the same as the processes of S23 and S24 in FIG. 2 with the above-mentioned changes.

[0067] In the process of S25A, the brake 12 is actuated (S25A). Because the brake 12 is an excitation-activated brake, the brake 12 is excited to brake the traveling mechanism 11 by the brake 12. Thereafter, the process is executed again from S10A.

[0068] The present embodiment described above in detail has the advantages of the first embodiment with the above-mentioned changes (advantages equivalent to the first embodiment) as well as the following advantages. Here, only advantages different from the first embodiment will be described.

[0069] The higher the height of the boom 41 and the bucket 151, the greater the potential energy possessed by the boom 41 and the bucket 151. In this regard, when the ECU 35 causes the traveling MG 13 to generate regenerative power using the kinetic energy of the traveling mechanism 11, the ECU 35 executes a regenerative operation to drive the boom MG 42 and the bucket MG 152 with the regenerative power generated by the regenerative power generation, thereby raising the boom 41 and the bucket 151 above their current height. Therefore, the regenerative power generated by the regenerative power generation of the traveling MG 13 can be converted into potential energy of the boom 41 and the bucket 151 and recovered. Therefore, the ECU 35 of the wheel loader 110 can add means for recovering regenerative power other than the battery 70.

[0070] When the traveling mechanism 11 is caused to generate power regeneratively using the kinetic energy of the traveling mechanism 11, the ECU 35 sequentially raises the boom 41 and the bucket 151 from their current heights in accordance with a preset priority order. This makes it possible to prevent the boom 41 and the bucket 151 from operating in an inappropriate order.

[0071] Specifically, when the boom 41 and the bucket 151 are raised above their current heights, the boom 41 is raised above its current height and then the bucket 151 is raised above that height. More specifically, the boom 41 is raised to the maximum lifting angle αmax, and then the bucket 151 is lifted. For this reason, raising the boom 41 first makes it easier to ensure the operator's field of vision, and raising the bucket 151 after the boom 41 can prevent the bucket 151 from colliding with the surroundings.

[0072] The first and second embodiments can be modified as follows: The same parts as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof will be incorporated herein.

[0073] In the first embodiment, after the boom 41 and the arm 51 are raised to a target height (lifting angle α) by the regenerative operation, the ECU 35 may calculate the height (liftable angle) that can be raised from the target height to an upper limit height (maximum lifting angle αmax) or the amount of energy that can be recovered by the regenerative operation of raising the boom 41 and the arm 51 from the target height to the upper limit height. With this configuration, after the boom 41 and the arm 51 are raised to the target height by the regenerative operation, the height to which the boom 41 and the arm 51 can be raised or the amount of energy that can be recovered in the next regenerative operation can be calculated. Therefore, these calculated amounts can be used in the next regenerative operation. For example, one of the boom 41 and the arm 51 that can be raised to a higher height or has a higher amount of recoverable energy in the next regenerative operation may be preferentially raised in the next regenerative operation. Note that the same effects can be achieved in the second embodiment by replacing "arm 51" with "bucket 151."

[0074] As shown by dashed lines in FIG. 1 , the power shovel 10 may be equipped with a first notification device 61 and a second notification device 62. The first notification device 61 notifies the operator of the power shovel 10 that a regenerative operation will be performed, for example, by voice or an alarm sound. The second notification device 62 notifies workers around the power shovel 10 that a regenerative operation will be performed, for example, by voice or an alarm sound. The ECU 35 executes a regenerative operation after activating the first notification device 61 and the second notification device 62. This configuration makes it possible to notify the operator of the power shovel 10 and surrounding workers in advance that a regenerative operation will be performed, thereby ensuring the safety of the operator of the power shovel 10 and surrounding workers. As shown by dashed lines in FIG. 5 , the wheel loader 110 may also be equipped with a first notification device 61 and a second notification device 62. This configuration makes it possible to achieve the same effects in the wheel loader 110.

[0075] As shown by the dashed line in FIG. 1 , the power shovel 10 may be equipped with a regenerative operation switch 63. The regenerative operation switch 63 is switched by the operator between performing regenerative operation (ON) and stopping regenerative operation (OFF). In other words, the operator can prohibit regenerative operation by operating the regenerative operation switch 63 to OFF. The wheel loader 110 may also be equipped with a regenerative operation switch 63.

[0076] When utilizing the potential energy of the boom 41 and the arm 51, the ECU 35 can also perform the following control. That is, the ECU 35 lowers the boom 41 and the arm 51 from their current heights, thereby causing the boom MG42 and the arm MG52 to generate regenerative power using the potential energy of the boom 41 and the arm 51, respectively. The ECU 35 may then charge the battery 70 with the regenerative power generated by the regenerative power generation of the boom MG42 and the arm MG52. Note that by replacing "arm 51" with "bucket 151" and "arm MG52" with "bucket MG152," the same effects can be achieved in the second embodiment.

[0077] In the first embodiment, the ECU 35 can also operate the brake 22 without driving the auxiliary device 80 with the regenerative electric power generated by regeneration. In the second embodiment, the ECU 35 can also operate the brake 12 without driving the auxiliary device 80 with the regenerative electric power generated by regeneration.

[0078] In the first embodiment, when regenerative power is generated by the swing MG 23, the ECU 35 can also simultaneously lift the boom 41 and the arm 51 as a regenerative operation. Furthermore, in the first embodiment, when regenerative power is generated by the swing MG 23, the ECU 35 can also lift the arm 51 as a regenerative operation and then lift the boom 41, as long as the safety of workers around the power shovel 10 can be ensured. Furthermore, in the first embodiment, when regenerative power is generated by the swing MG 23, the ECU 35 can also alternately lift the boom 41 and the arm 51 by a predetermined amount as a regenerative operation. In this case, if the boom 41 or the arm 51 reaches its upper limit height, it is preferable to terminate the lifting of the boom 41 or the arm 51 that has reached the upper limit height. Furthermore, in the regenerative operation, the ECU 35 can also lift only one of the boom 41 and the arm 51, without lifting the other. In the above, the second embodiment can be similarly modified by replacing "power shovel 10" with "wheel loader 110," "swinging MG23" with "traveling MG13," and "arm 51" with "bucket 151."

[0079] The power shovel 10 and the wheel loader 110 may be provided with a capacitor in addition to the battery 70, and the regenerated power generated by regenerative power generation may be stored in the capacitor. The ECU 35 may determine whether or not the capacitor can store the power, and if it determines that the capacitor can store the power, store the power generated by regenerative power generation in the capacitor, and if it determines that the capacitor cannot store the power, execute a regenerative operation (S17, S21) to recover the regenerated power. Alternatively, the regenerated power may be preferentially stored in the capacitor, and then the remaining regenerated power may be charged to the battery 70.

[0080] As shown in FIG. 8 , the power shovel 10 may include an engine 71, an MG 72 driven by the engine, and an INV 73 connected to the MG 72, the battery 70, and the first INV unit 31. The power shovel 10 may be configured to drive the traveling MG 13, the swing MG 23, the boom MG 42, and the arm MG 52 via the INV 73 using electric power generated by the MG 72 based on the driving force of the engine 71. For example, as shown in FIG. 9 , after the processing of S14, the engine 71 is stopped (S14A). The series of processing shown in FIG. 9 is executed by the ECU 35 during warm-up of the engine 71 and when the operator has stopped operating the swing mechanism 21. Even in this case, the ECU 35 can cause at least one of the traveling MG 13 and the swing MG 23 to perform regenerative operation using the regenerative electric power generated by the regenerative power generation when causing the traveling MG 13 and the swing MG 23 to perform regenerative operation.

[0081] The regenerative operation during regenerative power generation described above in the first embodiment, the second embodiment, and their modified examples can also be applied to work machines such as forklifts and self-propelled robotic arms. The forklift (work machine) includes a first motor generator, a traveling mechanism (driven part) driven by the first motor generator, a second motor generator, and a fork (work mechanism) driven by the second motor generator and performing work while changing its height. The self-propelled robotic arm (work machine) includes a first motor generator, a traveling mechanism (driven part) driven by the first motor generator, a second motor generator, and a robotic arm (work mechanism) driven by the second motor generator and performing work while changing its height. In other words, the regenerative operation during regenerative power generation described above can be applied to work machines that include at least one driven part driven by the first motor generator and at least one work mechanism driven by the second motor generator and performing work while changing its height.

[0082] The above-described embodiment and modifications may be combined within the scope of possible combinations.

[0083] Characteristic configurations extracted from the above-described embodiments and modifications will be described below. [Configuration 1] at least one first motor generator (13, 23) for driving and generating electricity; at least one driven part (11, 21) driven by the first motor generator; at least one second motor generator (42, 52) for driving and generating electricity; at least one working mechanism (41, 51, 151) driven by the second motor generator and working while changing height; A control device (35) adapted to a work machine (10, 110) including the first motor-generator and the second motor-generator, the control device controlling the operation of the first motor-generator and the second motor-generator, The control device is a control device for a work machine that, when causing the first motor generator to generate regenerative power using the kinetic energy of the driven part, drives the second motor generator with the regenerative power generated by the regenerative power generation, thereby performing a regenerative operation to raise the work mechanism above its current height. [Configuration 2] The work machine includes an operating unit (60) that is operated by an operator to cause the work mechanism to perform work, 2. The control device for a work machine according to configuration 1, wherein the control device prohibits the regenerative operation when the operating unit is operated by the operator and the work mechanism is working. [Configuration 3] 3. The control device for a work machine according to configuration 1 or 2, wherein the control device calculates a target height of the work mechanism required to convert the kinetic energy of the driven part into potential energy of the work mechanism through the regenerative operation, and raises the work mechanism to the target height. [Configuration 4] The height to which the working mechanism can be raised is limited to an upper limit height or less, 4. The control device for a work machine according to configuration 3, wherein the control device terminates the regenerative operation when the height of the work mechanism reaches the upper limit height. [Configuration 5] the work machine includes at least one power storage device (70) capable of storing electric power regenerated by the first motor generator; The control device for a work machine according to any one of configurations 1 to 4, wherein the control device determines whether or not the regenerative power generated by the regenerative power generation can be stored in the power storage device, and if it is determined that the regenerative power generated by the regenerative power generation can be stored, causes the power storage device to store the regenerative power generated by the regenerative power generation, and if it is determined that the regenerative power cannot be stored, causes the regenerative operation to be performed. [Configuration 6] the work machine includes a plurality of the second motor-generators and a plurality of the work mechanisms, The control device for a work machine according to any one of configurations 1 to 5, wherein when the control device causes the first motor generator to generate regenerative power using the kinetic energy of the driven parts, the control device drives the second motor generators using the regenerative power generated by the regenerative power generation, thereby raising the work mechanisms above their current heights. [Configuration 7] The control device for a work machine according to configuration 6, wherein the control device, when causing the first motor generator to generate regenerative power using the kinetic energy of the driven parts, sequentially raises the plurality of work mechanisms above their current heights in accordance with a preset priority order. [Configuration 8] The plurality of working mechanisms include a boom (41) and an arm (51) attached to the boom, A control device for a work machine according to configuration 7, wherein when the control device causes the first motor generator to generate regenerative power using the kinetic energy of the driven part, the control device raises the boom above its current height and then raises the arm above its current height. [Configuration 9] The plurality of working mechanisms include a boom (41) and a bucket (151) attached to the boom; A control device for a work machine according to configuration 7, wherein when causing the first motor generator to generate regenerative power using the kinetic energy of the driven part, the control device raises the boom above its current height and then raises the bucket above its current height. [Configuration 10] The work machine includes at least one electric accessory (80); The height to which the working mechanism can be raised is limited to an upper limit height or less, The control device for a work machine according to any one of configurations 1 to 9, wherein when the heights of all of the work mechanisms have reached the upper limit height due to the regenerative operation and the first motor generator is caused to generate regenerative power using the kinetic energy of the driven parts, the control device drives the electric accessory with the regenerative power generated by the regenerative power generation. [Configuration 11] The work machine includes a brake (12, 22) that converts the kinetic energy of the driven part into heat and consumes it, 11. The control device for a work machine according to configuration 10, wherein the control device activates the brake when the heights of all of the work mechanisms have reached the upper limit height due to the regenerative operation, all of the electric accessories have been driven for a predetermined time, and the driven parts have kinetic energy to be consumed. [Configuration 12] The control device for a work machine according to configuration 4, wherein, after the control device has raised the working mechanism to the target height by the regenerative operation, the control device calculates a height that can be raised from the target height to the upper limit height, or an amount of energy that can be recovered by the regenerative operation to raise the working mechanism from the target height to the upper limit height. [Configuration 13] 13. The control device for a work machine according to any one of configurations 1 to 12, wherein the control device causes the second motor generator to generate regenerative power using potential energy possessed by the work mechanism by lowering the work mechanism from its current height. [Configuration 14] The work machine includes a first notification device (61) that notifies an operator of the work machine that the regenerative operation will be performed, and a second notification device (62) that notifies workers around the work machine that the regenerative operation will be performed, 14. The control device for a work machine according to any one of configurations 1 to 13, wherein the control device executes the regenerative operation after activating the first notification device and the second notification device. [Configuration 15] A control device for a work machine according to any one of configurations 1 to 14; at least one first motor-generator; At least one of the driven parts; at least one second motor-generator; At least one of the working mechanisms; A work machine comprising: [Explanation of symbols]

[0084] 10...power shovel, 11...traveling mechanism, 13...traveling MG, 21...swing mechanism, 23...swinging MG, 35...ECU, 41...boom, 42...boom MG, 51...arm, 52...arm MG, 110...wheel loader, 151...bucket.

Claims

1. At least one first motor generator (13, 23) for driving and generating electricity; at least one driven part (11, 21) driven by the first motor generator; at least one second motor generator (42, 52) for driving and generating electricity; At least one working mechanism (41, 51, 151) driven by the second motor generator and working while changing height; A control device (35) that is applied to a work machine (10, 110) and controls operation of the first motor generator and the second motor generator, The control device is a control device for a work machine that, when causing the first motor generator to generate regenerative power using the kinetic energy of the driven part, drives the second motor generator with the regenerative power generated by the regenerative power generation, thereby performing a regenerative operation to raise the work mechanism above its current height.

2. The work machine includes an operation unit (60) that is operated by an operator to cause the work mechanism to perform work, The control device for a work machine according to claim 1 , wherein the control device prohibits the regenerative operation when the operating unit is operated by the operator and the work mechanism is performing work.

3. 3. The control device for a work machine according to claim 1, wherein the control device calculates a target height of the work mechanism required to convert kinetic energy of the driven part into potential energy of the work mechanism through the regenerative operation, and raises the work mechanism to the target height.

4. The height to which the working mechanism can be raised is limited to an upper limit height or less, The control device for a work machine according to claim 3 , wherein the control device terminates the regenerative operation when the height of the work mechanism reaches the upper limit height.

5. the work machine includes at least one power storage device (70) capable of storing electric power regenerated by the first motor generator, 3. The control device for a work machine according to claim 1 or 2, wherein the control device determines whether or not the regenerative power generated by the regenerative power generation can be stored in the power storage device, and stores the regenerative power generated by the regenerative power generation in the power storage device when it is determined that the power can be stored, and performs the regenerative operation when it is determined that the power cannot be stored.

6. the work machine includes a plurality of the second motor-generators and a plurality of the work mechanisms, 3. The control device for a work machine according to claim 1 or 2, wherein, when causing the first motor generator to generate regenerative power using kinetic energy possessed by the driven parts, the control device drives the plurality of second motor generators using the regenerative power generated by the regenerative power generation to raise the plurality of work mechanisms above their current heights.

7. 7. The control device for a work machine according to claim 6, wherein the control device, when causing the first motor generator to generate regenerative power using kinetic energy possessed by the driven parts, sequentially raises the plurality of work mechanisms above their current heights in accordance with a preset priority order.

8. The plurality of working mechanisms include a boom (41) and an arm (51) attached to the boom; 8. A control device for a work machine according to claim 7, wherein, when causing the first motor generator to generate regenerative power using kinetic energy possessed by the driven part, the control device raises the boom above its current height and then raises the arm above its current height.

9. The plurality of working mechanisms include a boom (41) and a bucket (151) attached to the boom; 8. A control device for a work machine according to claim 7, wherein, when causing the first motor generator to generate regenerative power using kinetic energy possessed by the driven part, the control device raises the boom above its current height and then raises the bucket above its current height.

10. the work machine includes at least one electric accessory (80); The height to which the working mechanism can be raised is limited to an upper limit height or less, 3. The control device for a work machine according to claim 1, wherein when the heights of all of the work mechanisms have reached the upper limit height due to the regenerative operation and the first motor generator is caused to generate regenerative power using kinetic energy possessed by the driven parts, the control device drives the electric accessory with the regenerative power generated by the regenerative power generation.

11. The work machine includes a brake (12, 22) that converts kinetic energy of the driven part into heat and consumes it, 11. The control device for a work machine according to claim 10, wherein the control device activates the brake when the heights of all of the work mechanisms have reached the upper limit height due to the regenerative operation, all of the electric accessories have been driven for a predetermined time, and the driven parts have kinetic energy to be consumed.

12. 5. The control device for a work machine according to claim 4, wherein, after the working mechanism has been raised to the target height by the regenerative operation, the control device calculates a height that can be raised from the target height to the upper limit height, or an amount of energy that can be recovered by the regenerative operation that raises the working mechanism from the target height to the upper limit height.

13. 3. The control device for a work machine according to claim 1, wherein the control device causes the second motor generator to generate regenerative power using potential energy of the work mechanism by lowering the work mechanism below a current height.

14. The work machine includes a first notification device (61) that notifies an operator of the work machine that the regenerative operation will be performed, and a second notification device (62) that notifies workers around the work machine that the regenerative operation will be performed, The control device for a work machine according to claim 1 or 2, wherein the control device executes the regenerative operation after activating the first notification device and the second notification device.

15. The control device for a work machine according to claim 1 or 2; at least one first motor-generator; At least one of the driven parts; at least one second motor-generator; At least one of the working mechanisms; A work machine comprising:

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