Construction machine

Abstract

The disclosed technology is a construction machine (1) able to translate according to a longitudinal axis (X1) with respect to a reference plane (P1), comprising a base (9), an active member (11) and a first rotary actuator (110) having two ends, a first end being rigidly fixed to the base (9) and a second end being rigidly fixed to the active member (11), the second end being mobile in rotation about a first rotation axis parallel to the longitudinal axis (X1) with respect to the first end, wherein the first rotary actuator is an electrical rotary actuator comprising an electric motor intended to be supplied in electrical power and deliver a rotational force to the active member (11) in a first rotational direction and a second, opposite the first, rotational direction, about the first rotation axis depending on a command provided by a control unit to the first rotary actuator.

Description

TECHNICAL FIELD

[0001] The disclosure relates generally to construction machines. In particular aspects, the disclosure relates to a construction machine having an active member with at least one degree of freedom in rotation. The disclosure can be applied for example in low-duty or medium-duty construction machines. Although the disclosure may be described with respect to a particular vehicle such as an excavator, the disclosure is not restricted to any particular vehicle.BACKGROUND

[0002] In this document, the framework of the disclosed technology will be described with the example of an excavator. As it will appear clearly from the description of the disclosed technology, a person skilled in the art will understand that the disclosed technology may be applied to any construction machine comprising an active member (or more than one) with one degree of freedom in rotation. Therefore, the example of the excavator is to be considered as a non-limiting example of the disclosed technology.

[0003] Nowadays, for the sake of environmental sustainability, there is a shift from fossil fuel-powered machines towards electric-powered machines. This transition is also effective in the field of construction and heavy equipment, such as excavators.

[0004] A first step of electrification was performed by replacing the internal combustion engine of an excavator by an electrical power source, such as a Lithium-ion battery. The actuation chain for actuating the active member of the excavator (that is to say the boom, the arm and the bucket) typically remains a hydraulic actuated chain based on linear driving cylinders as a construction machine like an excavator needs to provide a high level of power-to-weight ratio while ensuring a long operating life.

[0005] With the focus on electrification, another solution was developed in which the hydraulic architecture of the excavator was replaced with an electric architecture which incorporates electromechanical linear actuators. Such a solution presents some drawbacks amongst which the weight of the overall transmission chain. Indeed, in order to achieve similar performances as those obtained by a hydraulic transmission chain, it is necessary to equip electromechanical linear actuators with reducers. Furthermore, the integration of reducers on the electric motors of the electromechanical linear actuators lead to a cumbersome solution that significantly reduces the visibility of the surrounding environment by the operator of the excavator. Such an electric architecture is therefore hardly compatible with construction machines.

[0006] The disclosed technology falls within this context. It aims at offering an electrical construction machine presenting a compact integration of the actuators of the active member, thereby ensuring safety and zero tailpipe emissions. Other advantages of the disclosed technology will be explained in the description below.SUMMARY

[0007] According to a first aspect of the disclosure, a construction machine able to translate according to a longitudinal axis with respect to a reference plane, comprises at least a base, an active member and a first rotary actuator having two ends, a first of the two ends of the first rotary actuator being rigidly fixed to the base and a second of the two ends of the first rotary actuator being rigidly fixed to the active member, the second end of the first rotary actuator being mobile in rotation about a first rotation axis parallel to the longitudinal axis with respect to the first end of the first rotary actuator, wherein the first rotary actuator is an electrical rotary actuator comprising an electric motor intended to be supplied in electrical power by an electrical power source and delivers a rotational force to the active member in a first rotational direction and in a second rotational direction, opposite the first rotational direction, about the first rotation axis depending on a command provided by a control unit to the first rotary actuator. Rigidly fixed is to be understood as rigidly attached.

[0008] The first aspect of the disclosure may seek to provide a compact construction machine as a rotary actuator is more compact than a linear actuator. Indeed, a rotary actuator produces a rotational motion, which often requires less space than the linear travel that would be required for a linear actuator to generate a similar force over the same distance. It results in a compact construction machine as rotary actuator can be at least as efficient as linear actuator, or even more efficient, and they are suitable for integration between a base and an active member intended to be rotated.

[0009] The integration of an electrical rotary actuator into a construction machine requires to reconsider the actuation chain of the active member. The disclosed technology offers a powerful alternative for actuation as an electrical rotary actuator can achieve high speeds and responsiveness compared to linear actuators. Especially, the continuous rotation capability of rotary actuators is highly suited for tasks requiring a rapid movement or continuous operation. The disclosed technology relies on a new paradigm for actuating members in relation to each other. In activities in which the movements were obtained by linear actuators, the disclosed technology switches to rotational movements by replacing a linear actuator with a rotary actuator.

[0010] Optionally in some examples, including in at least one preferred example, the active member comprises a proximal member to which the second end of the first rotary actuator is rigidly fixed and a distal member, the construction machine further comprising a second rotary actuator having two ends, a first of the two ends of the second rotary actuator being rigidly fixed to the proximal member and a second of the two ends of the second rotary actuator being rigidly fixed to the distal member, the second end of the second rotary actuator being mobile in rotation about a second rotation axis parallel to the longitudinal axis with respect to the first end of the second rotary actuator.

[0011] Optionally in some examples, including in at least one preferred example, the distal member comprises an intermediate member having two ends, a first end of which being rigidly fixed to the second end of the second rotary actuator, and a final member, the construction machine further comprising a third rotary actuator having two ends, a first of the two ends of the third rotary actuator being rigidly fixed to the intermediate member and a second of the two ends of the third rotary actuator being rigidly fixed to the final member, the second end of the third rotary actuator being mobile in rotation about a third rotation axis parallel to the longitudinal axis with respect to the first end of the third rotary actuator.

[0012] Thanks to the integration of two or three, or even more, rotary actuators, it is possible to make the active member have any trajectory the operator wants to. The integration of at least two or three electrical rotary actuators in the actuation chain of the construction machine enables to reduce tailpipe emissions as the motors are electric. On top of providing a compact solution, the electrical rotary actuators have a positive impact on the environment. The electric motors of the electrical rotary actuators contribute to the reduction of air pollution. It is to be noted that such motors are significantly quieter than other types of motor. It results in improved working conditions on site, particularly in urban areas or noise-sensitive locations.

[0013] Optionally in some examples, including in at least one preferred example, at least one of the rotary actuators of the active member is an electrical rotary actuator comprising an electric motor intended to be supplied in electrical power by an electrical power source and delivers a rotational force to the member to which the second end is rigidly fixed in a first rotational direction or in a second rotational direction, opposite the first rotational direction, about the rotation axis of said rotary actuator depending on a command provided by the control unit to said rotary actuator. Additionally to the advantages that were discussed above, electric motors form an energy-efficient solution. Following this, less energy is required to achieve performance. Electric motors also have the advantage of reduced maintenance costs as they have fewer moving parts and no need for oil changes.

[0014] Optionally in some examples, including in at least one preferred example, the construction machine comprises a chassis, the base being connected to the chassis, wherein the base is mobile in rotation about a vertical axis perpendicular to the longitudinal axis with respect to the chassis. The active member is mobile in rotation about the first rotational axis with respect to the base. The mobility in rotation of the base about the vertical axis with respect to the chassis adds to the mobility in rotation of the active member about the first rotational axis with respect to the base. It results in that the active member can reach any desired position.

[0015] Optionally in some examples, including in at least one preferred example, the construction machine comprises an electrical power source intended to supply electrical power to the electrical rotary actuators.

[0016] Optionally in some examples, including in at least one preferred example, the construction machine comprises a control unit configured to receive an input signal and to provide commands to at least one of the rotary actuators based on the input signal and instructions stored on a memory of the control unit. The control unit is therefore configured to control the activation and operation of the rotary actuators. It enables to ensure that commands corresponding to input signals from the operator are transmitted to the active member, and more particularly to each concerned member in a well-defined sequence of instructions.

[0017] Optionally in some examples, including in at least one preferred example, each of the electrical rotary actuators comprises at least a motor drive connected to the electric motor and configured to regulate speed and torque of the electric motor in accordance with a command received from the control unit. A technical benefit may include speed and torque regulation of the electrical motor to which it is associated. It allows to control the force that the electric motor applies on the member connected to the electrical rotary actuator. When equipped with a sensor, the electrical rotary actuator allows a closed-loop control. In this case, the sensor captures the values of the speed and torque delivered by the electric motor, the control unit may process these data and sends updated commands to the motor drive to allow a more precise control of the movement of the concerned member.

[0018] Optionally in some examples, including in at least one preferred example, each of the electrical rotary actuators comprises at least an encoder connected to the electric motor and configured to monitor at least one parameter amongst a position and a speed of the electric motor, and send said at least one parameter to the control unit. A technical benefit may include a closed-loop control of the electrical rotary actuators. Further to the monitoring operated by the encoder, real-time values of position and torque of the electric motor are sent to the control unit. The control unit can process these data and update the commands to be sent to each the electrical rotary actuators depending on the input data from the operator and the real-time values of each electrical rotary actuator.

[0019] Optionally in some examples, including in at least one preferred example, each of the electrical rotary actuators comprises at least a static brake configured to immobilize the second end of said electrical rotary actuator when an emergency situation is detected by the control unit. A technical benefit of this technical feature is to maintain the electrical rotary actuator in position when it is activated, for example when a sudden shock is detected or when a motor shuts down. Thanks to the static brakes, the electrical rotary actuators are held in place, which means that their movement is stopped. It follows that any unwanted movement is prevented, thereby ensuring the safety of the construction machine in case of a sudden shutdown or failure. It is to be noted that emergency situation also includes a situation in which the operator stops the construction machine.

[0020] Optionally in some examples, including in at least one preferred example, each of the electric motor is configured to operate as an electric generator when the command provided to the electrical rotary actuator is intended to rotate the member to which the second end is rigidly fixed so as to reduce an angle value between said member and an axis extending according to the gravity. A technical benefit may include energy recovery from the electric motors operating in a regenerative braking mode. In this mode, the electric motors operate as an electric generator. The kinetic energy of the downward motion of the member(s) is converted into electrical energy. The construction machine therefore takes advantage of the effect of gravity to recover energy and sends it back to the electrical power source for recharging it. It leads to an enhanced energy efficiency of the construction machine.

[0021] Optionally in some examples, including at least one preferred example, at least one of the rotary actuators presents a single degree of freedom, said single degree of freedom being the degree of freedom in rotation about its rotational axis. Each rotary actuator defines one degree of freedom in rotation about its rotational axis. The combination of rotary actuators placed in series enables to achieve any possible trajectory in a plane. When required, as it is the case of an excavator, the additional degree of freedom of rotation about the vertical axis enables to achieve all said trajectories in all planes about the vertical axis. It enables to perform a large variety of movements of the active member thanks to a kinematics that is easy to control.

[0022] Optionally in some examples, including in at least one preferred example, the construction machine is a trailer, the proximal member being a skip and the distal member being a gate of the skip.

[0023] Optionally in some examples, including in at least one preferred example, the construction machine is an excavator, the base comprising a cab, the proximal member being a boom, the intermediate member being an arm and the final member being a bucket.

[0024] Optionally in some examples, including in at least one preferred example, at least one of the proximal member and the intermediate member comprises a hollow cavity, the construction machine comprising electrical wires to connect electrically the electrical power source, respectively the control unit, to the electrical rotary actuators, said electrical wires extending inside the hollow cavities. It means that the construction machine comprises electrical wires connecting electrically the electrical power source to the electrical rotary actuators, and / or the construction machine comprises electrical wires connecting electrically the control unit to the electrical rotary actuators. As the electrical wires extend inside the hollow cavities, they are protected them from external constraints. This arrangement ensures durability throughout the lifecycle of the excavator.

[0025] The disclosed aspects, examples (including any preferred examples), and / or accompanying claims may be suitably combined with each other as would be apparent to anyone of ordinary skill in the art. Additional features and advantages are disclosed in the following description, claims, and drawings, and in part will be readily apparent therefrom to those skilled in the art or recognized by practicing the disclosure as described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Examples are described in more detail below with reference to the appended drawings. FIG. 1 is a perspective view of an exemplary excavator according to an example. FIG. 2 is a schematic representation of the degrees of freedom of an exemplary construction machine according to an example. FIG. 3 is a schematic representation of the degrees of freedom of another exemplary construction machine according to an example. FIG. 4 schematically represents details of a rotary actuator of the exemplary construction machine presented in figure 2. DETAILED DESCRIPTION

[0027] The detailed description set forth below provides information and examples of the disclosed technology with sufficient detail to enable those skilled in the art to practice the disclosure.

[0028] FIG. 1 is a perspective view of an exemplary excavator according to an example. In this illustration, the construction machine is an excavator 1. As depicted, the excavator 1 is able to translate according to a longitudinal axis X1 with respect to a reference plane P1. In other words, the excavator 1 is able to move in a translating movement according to the axis X1. As represented, the reference plane P1 is horizontal but it could also be inclined as well. The construction machine 1 comprises a base 9. In the example of the excavator, the base 9 is the part of the construction machine that comprises the cab in which an operator is intended to be installed in order to drive and manipulate the excavator.

[0029] The construction machine 1 comprises at least an active member 11. As it will be explained in detail by way of examples, the active member 11 is to be understood as a working element of the construction machine 1. In the example of the excavator, the active member 11 comprises at least one of a arm, a boom, a bucket. Alternatively, the active member 11 may comprise a drill instead of a bucket. As it will be explained below, the disclosed technology is not limited to the working tool of the construction machine. The disclosed technology lies in the way the active member operates and how its components are integrated in relation to each other.

[0030] The construction machine 1 comprises a first rotary actuator 110 having two ends 111, 112. A first end 111 of the first rotary actuator 110 is rigidly fixed to the base 9. In other words, the first end 111 is mechanically secured to the base 9. A second end 112 of the first rotary actuator 110 is rigidly fixed to the active member 11.

[0031] The second end 112 of the first rotary actuator 110 is mobile in rotation about a first rotation axis Y1 parallel to the longitudinal axis X1 with respect to the first end 111 of the first rotary actuator 110. It results that the active member 11 is mobile in rotation around the first rotation axis Y1 with respect to the base 9.

[0032] According to a first aspect of the disclosure, the first rotary actuator 110 is an electrical rotary actuator comprising an electric motor 200 intended to be supplied in electrical power by an electrical power source 201 and deliver a rotational force to the active member 11 in a first rotational direction S1 or a second rotational direction S2, opposite the first rotational direction S1, about the first rotation axis Y1 depending on a command provided by a control unit 15 to the first rotary actuator 110.

[0033] The electrical rotary actuator transforms electric energy to mechanical rotation. The electric motor 200 of the electrical rotary actuator 110 may be a direct current (DC) motor, synchronous and asynchronous motor, alternating current (AC) motor, stepper motor, or a servomotor.

[0034] A DC motor presents a simple design and is easy to control. A brush motor uses the wound armature and a brushless motor uses a permanent-magnet rotor. A brushless DC motor is known to be efficient and reliable.

[0035] In a synchronous motor, the speed of the rotor and the frequency of the current flowing through the motor are synchronous. In an asynchronous motor, the speed of the rotor and the frequency of the current flowing through the motor are not the same.

[0036] A stepper motor is able to provide a continuous motion and a quick positioning within a short distance. It presents the advantage of being capable of high torque output and high accuracy, without needing a feedback system.

[0037] A servomotor combines a motor with a position-sensing device (like an encoder). It offers a precise control over angular displacement, velocity, and torque.

[0038] The electric motor comprises two main parts: a stator and a rotor. The stator is the stationary electrical component. It is rigidly fixed to the housing of the electric motor. The rotor is the rotating electrical component. It is located inside the stator and is mounted on the motor's shaft. The stator receives the electrical energy from an electric power source, creates a magnetic field that makes the rotor rotate, resulting in the rotation of the motor's shaft.

[0039] As defined above, the first end 111 of the first rotary actuator 110 that is rigidly fixed to the base 9 corresponds to the stator of the electric motor 200. The second end 112 of the first rotary actuator 110 corresponds to the output shaft of the electrical motor. The active member 11 is mechanically connected to the second end 112. The first rotary actuator 110 is disposed such that its second end 112 is mobile in rotation with respect to the first end 111 around a first rotation axis Y1 that is parallel to the longitudinal axis X1.

[0040] It follows that the active member 11 is mobile in rotation around the first rotation axis Y1 with respect to the base 9. The disclosed technology concerns a construction machine in which the rotation of the active member 11 is performed thanks to an electrical rotary actuator 110. On top of ensuring electrification of the mobility of the active member (i.e. no pollutants emission), such an electrical rotary actuator 110 offers a precise control of the positioning of the active member 11.

[0041] More details of the mobility of the active member 11 with respect to the base 9 will be given in relation to figure 2.

[0042] FIG. 2 is a schematic representation of the degrees of freedom of an exemplary construction machine 1 according to an example. This exemplary construction machine 1 may be any construction machine, a preferred example being an excavator. The construction machine 1 can translate according to the longitudinal axis X1.

[0043] The first end 111 of the first rotary actuator 110 is fixed to the base 9 of the excavator. The second end 112 of the first rotary actuator 110 is fixed to the active member 11. The active member 11 can rotate around the first rotation axis Y1.

[0044] In an example, the active member 11 may be a rod having two tips, the first tip being fixed to the second end 112 of the first rotary actuator 110 and the second tip being equipped with a working tool, such as a hammer or a hatchet. Further to the rotation of the active member 11 about the first rotation axis Y1, the working tool moves according to a circular trajectory centered on the first rotation axis Y1 and of a radius equal to the distance between the working tool and the first rotation axis Y1.

[0045] Optionally in some examples, including in at least one preferred example, the active member 11 comprises a proximal member 20 to which the second end 112 of the first rotary actuator 110 is rigidly fixed and a distal member 21. In this example, the construction machine further comprises a second rotary actuator 120. The second rotary actuator 120 is similarly to the first rotary actuator 110 in its general structure. In other words, the second rotary actuator 120 has two ends: a first end 121 and a second end 122. The first end 121 of the second rotary actuator 120 is rigidly fixed to the proximal member 20. The second end 122 of the second rotary actuator 120 is rigidly fixed to the distal member 21. Similarly to the first rotary actuator, the second end 122 of the second rotary actuator 120 is mobile in rotation about a second rotation axis Y2 parallel to the longitudinal axis X1 with respect to the first end 121 of the second rotary actuator 120.

[0046] In this example, the active member 11 is decomposed into two parts, the proximal member 20 and the distal member 21. The distal member 21 is articulated around the second rotary actuator 120. More exactly, the distal member 21 has a degree of freedom in rotation about the second rotation axis Y2 with respect to the proximal member 20.

[0047] It follows from what was described above that the second end 122 is mobile in rotation about the second rotation axis Y2 with respect to the first end 121, which is itself, through the proximal member 20, mobile in rotation about the first rotation axis Y1 with respect to the first end 111. The first rotary actuator 110 and the second rotary actuator 120 are mounted in series. The trajectory of the distal member 21 is the result of the combination of both rotations about the first rotation axis Y1 and the second rotation axis Y2.

[0048] Optionally in some examples, including in at least one preferred example, the distal member 21 comprises an intermediate member 22 and a final member 23. The intermediate member 22 has two ends 221 and 222. The first end 221 of the intermediate member 22 is rigidly fixed to the second end 122 of the second rotary actuator 120. The construction machine further comprises a third rotary actuator 130 having two ends 131, 132. A first end 131 of the third rotary actuator 130 is rigidly fixed to the intermediate member 22 and a second end 132 of the third rotary actuator 130 is rigidly fixed to the final member 23. The second end 132 of the third rotary actuator 130 is mobile in rotation about a third rotation axis Y3 parallel to the longitudinal axis X1 with respect to the first end 131 of the third rotary actuator 130.

[0049] In this example, the distal member 21 is decomposed into two parts, the intermediate member 22 and the final member 23. The final member 23 is articulated around the third rotary actuator 130. More exactly, the final member 23 has a degree of freedom in rotation about the third rotation axis Y3 with respect to the intermediate member 23.

[0050] As the distal member 21 has a trajectory resulting from the combination of both rotations about the first rotation axis Y1 and the second rotation axis Y2, the trajectory of the final member 23 is the result of the combination of the three rotations about the first rotation axis Y1, the second rotation axis Y2, and the third rotation axis Y3.

[0051] The second rotary actuator 120 and the third rotary actuator 130 might be any kind of rotary actuator. In other words, they may be a hydraulic or pneumatic-driven actuators. Optionally in some examples, including in at least one preferred example, at least one of the second and third rotary actuators 120, 130 of the active member 11 is an electrical rotary actuator comprising an electric motor 200. As mentioned before, such an electric motor 200 is intended to be supplied in electrical power by an electrical power source 201 and deliver a rotational force to the member to which the second end is rigidly fixed. The rotational force is directed either in the first rotational direction S1 or in the second rotational direction S2, opposite the first rotational direction S1, about the rotation axis of said rotary actuator 120, 130 depending on a command provided by the control unit 15 to said rotary actuator.

[0052] In a preferred example, both second and third rotary actuators 120, 130 are electrical rotary actuators. In this case, the whole actuation chain is electrified. Each member rigidly fixed to the second end of an electrical rotary actuator moves according to a well-controlled trajectory.

[0053] Optionally in some examples, including in at least one preferred example, the construction machine 1 comprises a chassis 10. The base 9 is connected to the chassis 10, and the base 9 is mobile in rotation about a vertical axis Z1 perpendicular to the longitudinal axis X1 with respect to the chassis 10. The connection between the base 9 and the chassis 10 may be performed by a couple pinion / crow. As an example, the crown might be fixed to the chassis 10 and the pinion might be fixed to the base. The pinion rotates about the vertical axis Z1 against the crown. It leads to the rotation about the vertical axis Z1 of the base 9. With respect to the reference plane P1, the movement of the active member 11 is a combination of its rotation about the first rotational axis Y1 with respect to the base 9 and the rotation of the base 9 about the vertical axis Z1. Similarly, the final member 23 follows a trajectory that results of the combination of four rotations: the rotation of the final member 23 about the axis Y3 with respect to the intermediate member 22, the rotation of the intermediate member 22 about the axis Y2 with respect to the proximal member 20, the rotation of the proximal member 20 about the axis Y1 with respect to the base 9, and the rotation of the base 9 about the axis Z1 with respect to the chassis 10.

[0054] In this latter example, the construction machine 1 is an excavator. The base 9 is a cab, the proximal member 20 is a boom, the intermediate member 22 is an arm and the final member 23 is a bucket.

[0055] FIG. 3 is a schematic representation of the degrees of freedom of another exemplary construction machine according to an example. In this example, the construction machine 2 is a trailer. The proximal member 20 is a skip and the distal member 21 is a gate of the skip.

[0056] The first end 111 of the first rotary actuator 110 is fixed to the base 9 of the trailer. In this example, the base 9 forms also the chassis 10. The second end 112 of the first rotary actuator 110 is fixed to the active member 11. The active member 11 can rotate around the first rotation axis Y1. The base 9 may translate according to the longitudinal axis X1. The active member 11 is mobile in rotation about the first rotational axis Y1 parallel to the longitudinal axis X1 with respect to the base 9. The active member 11 comprises the skip 20 and the gate 21.

[0057] The second end 112 of the first rotary actuator 110 is rigidly fixed to the skip (corresponding to the proximal member 20). Further to an actuation of the first rotary actuator, the skip can tilt according to the first rotational direction S1 or the second rotational direction S2 about the first rotational axis Y1. As depicted, the skip tilts according to the second rotational direction S2 to unload its cargo contained in the skip. The gate (corresponding to the distal member 21) should open. In order to place the gate in its open position, that is to say away from the skip, it should rotate about the second rotational axis Y2 in the first rotational direction S1. Therefore, the second end 122 of the second rotary actuator 120 rotates about the second rotational axis Y2 in the first rotational direction S1.

[0058] As for the example of figure 2, the rotary actuators are mounted in series, so that the movement of the distal member 21 is a combination of the movement of both rotary actuators.

[0059] Here again the second rotary actuator 120 may be a hydraulic or pneumatic-driven actuator. In a preferred example, the second rotary actuator 120 is an electrical rotary actuator. It results in an actuation chain totally electrified. The right positioning of the second end of each rotary actuator is ensured in regard to a positioning command.

[0060] FIG. 4 schematically represents details of a rotary actuator of the exemplary construction machine presented in figure 2. It means that the disclosed technology is described based on the example of an excavator. The rotary actuator that is shown in an exploded view is an exemplary rotary actuator. It corresponds to the third rotary actuator. It should be kept in mind that it could be the first rotary actuator and / or the second rotary actuator. The disclosed technology relies on the implementation of at least one electrical rotary actuator for the rotational movement of one member rigidly fixed to one end of the two ends of the rotary actuator in relation to another member rigidly fixed to the other end of the two ends of the rotary actuator. The person skilled in the art therefore understands that the elements of the third rotary actuator depicted in detail in figure 4 could equip similarly the first rotary actuator or the second rotary actuator, or the third rotary actuator, of a combination of both of the three rotary actuators, or all the rotary actuators of the construction machine. It is also to be underlined that the construction machine is depicted with three rotary actuators having a rotational axis parallel to the longitudinal axis, but the disclosed technology similarly applies to a construction machine having more than three rotary actuators.

[0061] Optionally in some examples, including in at least one preferred example, the construction machine comprises an electrical power source 201 intended to supply electrical power to the electrical rotary actuators 110, 120, 130. The electrical power source 201 may be a lithium-ion battery. It provides the necessary electrical energy to power the electrical motors and control electronics in the construction machine as it will appear in the further description of figure 4.

[0062] Optionally in some examples, including in at least one preferred example, the construction machine 1 comprises a control unit 15 configured to receive at least an input signal and to provide at least commands to at least one of the rotary actuators based on the input signal and instructions stored on a memory of the control unit 15. The control unit allows to process input signals and to send commands to the electrical motors.

[0063] As it will appear clearly when reading the description of the details of the disclosed technology below, the communication between the control unit 15 and the other elements of the construction machine 1 is realized through sensor signals and actuator commands. The transmission of signals and commands to or from the control unit 15 is performed by known communication means, such as wired connection, wireless connection, local area network bus, serial peripheral interface bus, etc. For these purposes, the control unit 15 may comprise at least one processor. Under the term processor, it should be understood at least one of a processor, microprocessor, Application Specific Integrated Circuit (also known under its acronym ASIC), electronic circuit, central processing unit. The control unit 15 may comprise at least one memory component (read only, programmable read only, random access, hard drive, etc.) able to store machine readable instructions accessible by the processor to provide the desired functionality.

[0064] The construction machine advantageously comprises a human-machine interface 202, for example an electrical joystick 202, to enable the control of the active member 11 of the construction machine 1. An operator may control the construction machine movements through the joystick 202. The joystick 202 may for example comprise a handle and buttons to transmit information to the control unit 15 to generate a particular movement of the active member. An operate activates the joystick 202 further to the movement of the active member 11 he / she wants to generate. Electrical signals are transmitted from the joystick to the control unit 15. When receiving these signals, the control unit 15 transmit commands to the electrical rotary actuators. These commands are determined based on the received signals and instructions stored on the control unit 15. It follows that the control unit 15 specifies the desired direction and speed of movement for the electrical rotary actuators. As an example, it can be cited a command for which it is intended to move the boom 20 up the first rotary actuator 110. The control unit 15 sends to the first rotary actuator 110 a command of rotating its second end about the first rotational axis Y1 in the rotational direction S1. The joystick 202 provides a real-time control and feedback to the operator to adjust his / her actions based on the reaction of the active member 11.

[0065] As illustrated, the joystick, and more generally the human-machine interface, is part of the construction machine 1. It is advantageously incorporated inside the cab of the excavator. Nevertheless, the disclosed technology operates similarly with a remote-controlled command. In other words, the human-machine interface could also be remote, i.e. outside the cab of the excavator. The remote-controlled command does not necessarily take the form of a joystick and can be any interface such as a touch panel to give movement instructions to the control unit 15 to be transmitted to the rotary actuator(s).

[0066] Optionally in some examples, including in at least one preferred example, each of the electrical rotary actuators 110, 120, 130 comprises a motor drive 210 connected to the electric motor 200, and configured to regulate speed and torque of the electric motor 200 in accordance with a command received from the control unit 15. As a non-limiting use-example, a motor drive of an electrical actuator converts the DC power from the electrical power source 201 into the necessary AC or DC power for driving the electrical rotary actuators, depending on the motor type that equips said electrical rotary actuator. The drive can be either integrated to the motor housing or placed in the excavator. As depicted in figure 4, the motor drive 210 of the third rotary actuator 130 is integrated inside the housing 211 of the electrical rotary actuator 130.

[0067] The housing 211 is a main part of the rotary actuator for protecting the internal components from shock impacts. As it encapsulates the electric motor, the housing 211 is a shock-resistant enclosure made of metal or other strong materials to prevent physical damage from external forces.

[0068] The role of the motor drive 210 is to regulate the speed and torque of the electrical motor 200, thereby controlling the force applied on the member connected to the second end of said electrical rotary actuator. The electrical rotary actuator may be equipped with sensors and a feedback mechanism to enable a closed-loop control. The sensors can retrieve the values of the real speed and torque, return this information to the feedback mechanism to allow a more precise control of the movement of the concerned member.

[0069] Optionally in some examples, including in at least one preferred example, each of the electrical rotary actuators 110, 120, 130 comprises an encoder 220 connected to the electric motor 200, and configured to monitor at least one parameter amongst a position and a speed of the electric motor 200, and send said at least one parameter to the control unit 15. Further to the monitoring operated by the encoder 220, the encoder is able to send real-time feedback to the control unit 15. Based on the information received by the encoder(s) 220, that can be interpreted as input data for the control unit 15, the control unit 15 adapt its commands sent to the electrical rotary actuator(s). The feedback information sent from the encoder(s) to the control unit 15 enables a closed-loop control of the electrical rotary actuators. Thanks to this feedback, it is ensured that the members of the construction machine maintain an accurate positioning and speed in accordance with the instructions for the operator. Furthermore it provides data for fault detection if any, as well as system diagnostics if necessary.

[0070] Based on predefined motion control instructions, the control unit 15 is configured to ensure smooth acceleration and deceleration of the active member. Thanks to the encoder, the control unit receives corresponding information when a shock occurs and sends a command to adjust the electrical motor's behavior, for example by reducing its speed, adjusting its torque, or even stopping the electrical motor temporarily to reduce potential damage. Each of the rotary actuators may comprise a force feedback sensor that is configured to constantly measure the force applied by the electrical motor. If an overload or a shock is detected by the force feedback sensor, the control unit may send a command to adjust the electric motor power in real-time to avoid excessive forces that could damage the electric motor.

[0071] Optionally in some examples, including in at least one preferred example, each of the electrical rotary actuators 110, 120, 130 comprises a static brake 230 configured to immobilize the second end of said electrical rotary actuator when an emergency situation is detected by the control unit 15. For example, in case a sudden drop of the electrical power level of the electrical power source 201 is detected by the control unit or if the motor power is cut, the control unit 15 sends a command to the static brakes 230 of the electrical rotary actuators 110, 120, 130 to activate. When activated, a static brake 230 holds the electrical rotary actuator in place to prevent unwanted movement of its second end with respect to its first end. The static brakes 230 ensure the safety of the construction machine in case of a sudden shutdown or failure.

[0072] The static brake may be a failsafe brake, also called safety brake. For safety reasons, such a brake is powered via a command of the control unit to be deactivated. The static brake 230 is a holding, or "Power-Off" brake that provides extra safety in applications where the load must remain in position in the event of power loss or equipment failure. It must indeed be able to engage in the event of a power loss. When a power outage occurs but also in the event of a breakdown or emergency stop, the static brake can automatically perform emergency braking by stopping rotating masses or maintaining a machine shaft position.

[0073] Optionally in some examples, including in at least one preferred example, each of the electric motor 200 is configured to operate as an electric generator when the command provided to the electrical rotary actuator is intended to rotate the member to which the second end is rigidly fixed so as to reduce an angle value between said member and an axis extending according to the gravity. In other words, the electrical rotary actuators may be equipped with a regenerative braking system, enabling energy recovery. It means that in normal operation, the driving force of the electrical motor comes from the electrical power source 201. Electrical energy is used by the electric motor and an electrical current flows across it. When the electric motor operates as an electric generator, i.e. during the regenerative mode, the electric motor increases the electromotive force of the circuit. This extra energy is directed toward the electrical power source 201. In the regenerative braking mode, the electrical motor 200 acts as an electrical generator. It converts the kinetic energy of the downward motion into electrical energy. This energy is sent back to the electrical power source 201 for recharging, thereby enhancing the overall energy efficiency of the construction machine.

[0074] Optionally in some examples, including in at least one preferred example, at least one of the rotary actuators 110, 120, 130 presents a single degree of freedom, said single degree of freedom being the degree of freedom in rotation about its rotation axis Y1, Y2, Y3. It means that the rotary actuator being an electrical rotary actuator has is second end that is mobile in rotation only about the corresponding rotational axis with respect to its first end.

[0075] Optionally in some examples, including in at least one preferred example, all the rotary actuators 110, 120, 130 present each a single degree of freedom, said single degree of freedom being the degree of freedom in rotation about its rotation axis Y1, Y2, Y3. It results that the trajectory of the final member 23 is obtained thanks to the combination of the rotation of the three rotary actuators about their single rotational axis in one plane perpendicular to the first, second, third rotational axis Y1, Y2, Y3. In the example of an excavator, the cab 9 is mobile in rotation about the vertical axis Z1 with respect to the chassis 10 of the excavator 1. As explained before, the rotation of the base 9 with respect to the chassis 10 may be performed by a couple pinion / crow. The crown might be fixed to the chassis 10 and the pinion might be fixed to the base. The pinion rotates about the vertical axis Z1 against the crown. It leads to the rotation about the vertical axis Z1 of the base 9. In one plane intersecting the vertical axis Z1, the active member 11 moves according to a well-defined kinematics involving the movement of one or more rotary actuators. The same applies to the other planes intersecting the vertical axis Z1 further to a rotation of the cab 9 about the vertical axis Z1 with respect to the chassis 10. The combination of movements obtained thanks to the mobilities of the active member and the rotation of the active member about the vertical axis Z1 results in the possibility of achieving any trajectory for the active member and the final member.

[0076] Optionally in some examples, including in at least one preferred example, each of the proximal member 20 and the intermediate member 22 comprises at least a hollow cavity. As an example, the hollow cavity may extend from one end to the other end of said member. It means that the cavity of the proximal member 22 forms a channel that extends from the second end 112 of the first rotary actuator 110 to the first end 121 of the second actuator 120. Similarly, the cavity of the intermediate member 20 forms a channel that extends from the second end 122 of the second rotary actuator 120 to the first end 131 of the third actuator 130. The construction machine 1 comprises electrical wires to connect electrically the electrical power source 201 to the electrical rotary actuators 110, 120, 130. The electrical wires extend inside the hollow cavities. The routing of the electric wires inside said members allows to protect them from environmental hazards and ensures durability throughout the lifecycle of the excavator. It may be noted that the electrical wires between the electrical power source 201 and the electrical rotary actuators 110, 120, 130, as well as the connection lines between the control unit and the electrical rotary actuators 110, 120, 130 are not depicted in figure 4 as extending inside the cavity of the members for the sake of understanding and readability of the figure.

[0077] The operation of a construction machine according to the disclosed technology will now be described in reference to the excavator. The person skilled in the art understands that the same can be applied to any construction machine having at least one rotary movement performed by way of an electrical rotary actuator.

[0078] In an excavator, the boom 20, the arm 22, and the bucket 23 are connected through a series of linkages and rotary actuators. The second rotary actuator 120 is mounted at the pivot point between the boom 20 and the arm 22, and the third rotary actuator 130 is mounted at the pivot point between the arm 22 and the bucket 23. The electric motors 200 are each housed in a robust frame 211 that can handle high loads, especially during heavy lifting or when the construction machine needs to exert substantial force.

[0079] The motor's shaft of each electric motor 200 can connect to a gearbox or reduction gear 205, which serves to amplify the torque delivered by the electric motor 200. This is especially necessary in excavators, where the electric motors 200 need to deliver a significant amount of rotational force to move large and / or heavy components.

[0080] The gearbox 205 may also be designed to reduce the load on the electric motor 200 and spread the shock forces. Such a gearbox helps to absorb high impacts, ensuring that the electric motor do not handle directly these shocks. This configuration allows to minimize the risk if electric motor damage due to shocks or overload of the excavator.

[0081] When starting the operation, an operator uses a human-machine interface, either onboard or remote, for example a joystick 202 to control the excavator's motion. Based on the movement applied to the joystick 202, electrical signals are sent to the control unit 15. These signals correspond to the desired movement direction and speed for the actuators, for example boom lift, arm extension, etc.

[0082] The control unit 15 receives the signal from the joystick 202 and processes them. It converts these signals into commands for the motor drives of the rotary actuators that control the rotary actuators. The control unit 15 also monitors feedback signals from the encoders 220 to adjust electrical motor operation in real-time. This control enables to ensure an accurate positioning and a smooth motion of the active member 11.

[0083] The motor drive 210 receives commands from the control unit 15 and adjusts the power sent to the electrical rotary actuator to achieve the desired motion. Thanks to the commands received from the control unit 15, the motor drive controls the torque and speed of the electric motor so as to ensure that the electric motor, and thus the rotary actuator, operates in accordance with the instructions of the operator.

[0084] Further to the commands received from the control unit 15, the electric motor rotates. The encoder 220 continuously monitors its position and speed. The encoder 220 sends this information back to the control unit 15 to maintain a precise control of the rotary actuator's motion.

[0085] A torque limiter may be incorporated into the rotary actuator to slip when the torque exceeds a set threshold, preventing the electric motor from being subjected to damaging levels of force. Each rotary actuator might also comprise a current sensor to detect sudden spikes in current (which correspond to high torque). This information is sent to the control unit that processes it and sends a command to limit power to the electric motor or reduce speed in real-time.

[0086] When a member is moving downward, for example when the boom goes down, the excavator can take advantage of the gravity effect to recover energy. The control unit 15 sends an instruction to the electric motor of said rotary actuator to operate in the regenerative mode. Said electrical rotary actuator generates electricity from the downward motion of the member connected to it. The generated electricity is sent back to the electrical power source 201, thereby replenishing the energy used during excavation tasks.

[0087] If a sudden loss of power occurs, for example due to an electrical power source depletion of an electrical motor shutdown, the static brakes 230 engage to hold the electrical rotary actuators 110, 120, 130 in position. It ensures that unintended movement does not occur, thereby ensuring a high safety level during the operation of the excavator.

[0088] The boom 20 and / or the arm 22 can each comprise a damping mechanism at key joints to absorb sudden shocks or high-impact forces. These damping mechanisms use shock-absorbing materials to dissipate energy, reducing the stress placed on the electrical motor. The damping allows to prevent abrupt movements or impacts from transferring to the electric motor, which could cause internal damage or misalignment.

[0089] At least one of the rotary actuators may comprise a soft stop feature connected to the motor drive. Instead of stopping abruptly when the member (for example the arm 20) reaches a limit, the control unit sends a command so that the electric motor 200 decelerates gradually. This controlled deceleration minimizes the risk of damaging the electric motor due to high inertia or a sudden stop.

[0090] Example 1: A construction machine 1, 2 able to translate according to a longitudinal axis X1 with respect to a reference plane P1, comprising at least a base 9, an active member 11 and a first rotary actuator 110 having two ends, a first 111 of the two ends of the first rotary actuator 110 being rigidly fixed to the base 9 and a second(112 of the two ends of the first rotary actuator 110 being rigidly fixed to the active member 11, the second end 112 of the first rotary actuator 110 being mobile in rotation about a first rotation axis Y1 parallel to the longitudinal axis X1 with respect to the first end 111 of the first rotary actuator 110, wherein the first rotary actuator 110 is an electrical rotary actuator comprising an electric motor 200 intended to be supplied in electrical power by an electrical power source 201 and deliver a rotational force to the active member 11 in a first rotational direction S1 and a second rotational direction S2, opposite the first rotational direction S1, about the first rotation axis Y1 depending on a command provided by a control unit 15 to the first rotary actuator 110.

[0091] Example 2: The construction machine of example 1, wherein the active member 11 comprises a proximal member 20 to which the second end 112 of the first rotary actuator 110 is rigidly fixed and a distal member 21, the construction machine further comprising a second rotary actuator 120 having two ends, a first 121 of the two ends of the second rotary actuator 120 being rigidly fixed to the proximal member 20 and a second 122 of the two ends of the second rotary actuator 120 being rigidly fixed to the distal member 21, the second end 122 of the second rotary actuator 120 being mobile in rotation about a second rotation axis Y2 parallel to the longitudinal axis X1 with respect to the first end 121 of the second rotary actuator 120.

[0092] Example 3: The construction machine of example 2, wherein the distal member 21 comprises an intermediate member 22 having two ends, a first end 221 of which being rigidly fixed to the second end 122 of the second rotary actuator 120, and a final member 23, the construction machine further comprising a third rotary actuator 130 having two ends, a first 131 of the two ends of the third rotary actuator 130 being rigidly fixed to the intermediate member 22 and a second 132 of the two ends of the third rotary actuator 130 being rigidly fixed to the final member 23, the second end 132 of the third rotary actuator 130 being mobile in rotation about a third rotation axis Y3 parallel to the longitudinal axis X1 with respect to the first end 131 of the third rotary actuator 130.

[0093] Example 4: The construction machine 1 of example 2 or 3, wherein at least one of the rotary actuators 120, 130 of the active member 11 is an electrical rotary actuator comprising an electric motor 200 intended to be supplied in electrical power by an electrical power source 201 and deliver a rotational force to the member to which the second end is rigidly fixed in a first rotational direction S1 or in a second rotational direction S2, opposite the first rotational direction S1, about the rotation axis Y2, Y3 of said rotary actuator 120, 130 depending on a command provided by the control unit 15 to said rotary actuator.

[0094] Example 5: The construction machine 1 of any one of examples 1 to 4, comprising a chassis 10, the base 9 being connected to the chassis 10, wherein the base 9 is mobile in rotation about a vertical axis Z1 perpendicular to the longitudinal axis X1 with respect to the chassis 10.

[0095] Example 6: The construction machine 1, 2 of any one of examples 1 to 5, comprising an electrical power source 201 intended to supply electrical power to the electrical rotary actuators 110, 120, 130.

[0096] Example 7: The construction machine 1, 2 of any one of examples 1 to 6, comprising a control unit 15 configured to receive an input signal and to provide commands to at least one of the rotary actuators based on the input signal and instructions stored on a memory of the control unit 15.

[0097] Example 8: The construction machine 1, 2 of example 7, wherein each of the electrical rotary actuators 110, 120, 130 comprises at least a motor drive 210 connected to the electric motor 200, and configured to regulate speed and torque of the electric motor 200 in accordance with a command received from the control unit 15.

[0098] Example 9: The construction machine 1, 2 of example 7 or 8, wherein each of the electrical rotary actuators 110, 120, 130 comprises at least an encoder 220 connected to the electric motor 200, and configured to monitor at least one parameter amongst a position, and a speed of the electric motor 200, and send said at least one parameter to the control unit 15.

[0099] Example 10: The construction machine 1, 2 of any one of examples 7 to 9, wherein each of the electrical rotary actuators 110, 120, 130 comprises at least a static brake 230 configured to immobilize the second end of said electrical rotary actuator when an emergency situation is detected by the control unit 15.

[0100] Example 11: The construction machine 1, 2 of any one of examples 7 to 10, wherein each of the electric motor 200 is configured to operate as an electric generator when the command provided to the electrical rotary actuator is intended to rotate the member to which the second end is rigidly fixed so as to reduce an angle value between said member and an axis extending according to the gravity.

[0101] Example 12: The construction machine 1, 2 of any one of examples 1 to 11, wherein at least one of the rotary actuators 110, 120, 130 presents a single degree of freedom, said single degree of freedom being the degree of freedom in rotation about its rotation axis Y1, Y2, Y3.

[0102] Example 13: The construction machine 2 of any one of examples 6 to 12 in combination with claim 3, wherein the construction machine is a trailer, the proximal member 20 being a skip and the distal member 21 being a gate of the skip.

[0103] Example 14: The construction machine 1 of any one of examples 5 to 12 in combination with example 4, wherein the construction machine is an excavator, the base 9 comprising a cab, the proximal member 20 being a boom, the intermediate member 22 being an arm and the final member 23 being a bucket.

[0104] Example 15: The construction machine 1 of example 14 in combination with example 3, wherein at least one of the proximal member 20 and the intermediate member 22 comprises a hollow cavity, the construction machine 1 comprising electrical wires to connect electrically the electrical power source 201, respectively the control unit 15, to the electrical rotary actuators 110, 120, 130, said electrical wires extending inside the hollow cavities.

[0105] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0106] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

[0107] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0108] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0109] It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.

Claims

1. A construction machine (1, 2) able to translate according to a longitudinal axis (X1) with respect to a reference plane (P1), comprising at least a base (9), an active member (11) and a first rotary actuator (110) having two ends, a first (111) of the two ends of the first rotary actuator (110) being rigidly fixed to the base (9) and a second (112) of the two ends of the first rotary actuator (110) being rigidly fixed to the active member (11), the second end (112) of the first rotary actuator (110) being mobile in rotation about a first rotation axis (Y1) parallel to the longitudinal axis (X1) with respect to the first end (111) of the first rotary actuator (110), wherein the first rotary actuator (110) is an electrical rotary actuator comprising an electric motor (200) intended to be supplied in electrical power by an electrical power source (201) and deliver a rotational force to the active member (11) in a first rotational direction (S1) and a second rotational direction (S2), opposite the first rotational direction (S1), about the first rotation axis (Y1) depending on a command provided by a control unit (15) to the first rotary actuator (110).

2. The construction machine (1, 2) according to claim 1, wherein the active member (11) comprises a proximal member (20) to which the second end (112) of the first rotary actuator (110) is rigidly fixed and a distal member (21), the construction machine further comprising a second rotary actuator (120) having two ends, a first (121) of the two ends of the second rotary actuator (120) being rigidly fixed to the proximal member (20) and a second (122) of the two ends of the second rotary actuator (120) being rigidly fixed to the distal member (21), the second end (122) of the second rotary actuator (120) being mobile in rotation about a second rotation axis (Y2) parallel to the longitudinal axis (X1) with respect to the first end (121) of the second rotary actuator (120).

3. The construction machine according to claim 2, wherein the distal member (21) comprises an intermediate member (22) and a final member (23), said intermediate member (22) having two ends, a first end (221) of which being rigidly fixed to the second end (122) of the second rotary actuator (120), the construction machine further comprising a third rotary actuator (130) having two ends, a first (131) of the two ends of the third rotary actuator (130) being rigidly fixed to the intermediate member (22) and a second (132) of the two ends of the third rotary actuator (130) being rigidly fixed to the final member (23), the second end (132) of the third rotary actuator (130) being mobile in rotation about a third rotation axis (Y3) parallel to the longitudinal axis (X1) with respect to the first end (131) of the third rotary actuator (130).

4. The construction machine (1) according to claim 2 or 3, wherein at least one of the rotary actuators (120, 130) of the active member (11) is an electrical rotary actuator comprising an electric motor (200) intended to be supplied in electrical power by an electrical power source (201) and deliver a rotational force to the member to which the second end is rigidly fixed in a first rotational direction (S1) or in a second rotational direction (S2), opposite the first rotational direction (S1), about the rotation axis (Y2, Y3) of said rotary actuator (120, 130) depending on a command provided by the control unit (15) to said rotary actuator.

5. The construction machine (1) according to any one of claims 1 to 4, comprising a chassis (10), the base (9) being connected to the chassis (10), wherein the base (9) is mobile in rotation about a vertical axis (Z1) perpendicular to the longitudinal axis (X1) with respect to the chassis (10).

6. The construction machine (1, 2) according to any one of claims 1 to 5, comprising an electrical power source (201) intended to supply electrical power to the electrical rotary actuators (110, 120, 130).

7. The construction machine (1, 2) according to any one of claims 1 to 6, comprising a control unit (15) configured to receive an input signal and to provide commands to at least one of the rotary actuators based on the input signal and instructions stored on a memory of the control unit (15).

8. The construction machine (1, 2) according to claim 7, wherein each of the electrical rotary actuators (110, 120, 130) comprises at least a motor drive (210) connected to the electric motor (200), and configured to regulate speed and torque of the electric motor (200) in accordance with a command received from the control unit (15).

9. The construction machine (1, 2) according to claim 7 or 8, wherein each of the electrical rotary actuators (110, 120, 130) comprises at least an encoder (220) connected to the electric motor (200), and configured to monitor at least one parameter amongst a position and a speed of the electric motor (200), and send said at least one parameter to the control unit (15).

10. The construction machine (1, 2) according to any one of claims 7 to 9, wherein each of the electrical rotary actuators (110, 120, 130) comprises at least a static brake (230) configured to immobilize the second end of said electrical rotary actuator when an emergency situation is detected by the control unit (15).

11. The construction machine (1, 2) according to any one of claims 7 to 10, wherein each of the electric motor (200) is configured to operate as an electric generator when the command provided to the electrical rotary actuator is intended to rotate the member to which the second end is rigidly fixed so as to reduce an angle value between said member and an axis extending according to the gravity.

12. The construction machine (1, 2) according to any one of claims 1 to 11, wherein at least one of the rotary actuators (110, 120, 130) presents a single degree of freedom, said single degree of freedom being the degree of freedom in rotation about its rotational axis (Y1, Y2, Y3).

13. The construction machine (2) according to any one of claims 6 to 12 in combination with claim 3, wherein the construction machine is a trailer, the proximal member (20) being a skip and the distal member (21) being a gate of the skip.

14. The construction machine (1) according to any one of claims 5 to 12 in combination with claim 4, wherein the construction machine is an excavator, the base (9) comprising a cab, the proximal member (20) being a boom, the intermediate member (22) being an arm and the final member (23) being a bucket.

15. The construction machine (1) according to claim 14 in combination with claim 3 and claim 7, wherein at least one of the proximal member (20) and the intermediate member (22) comprises a hollow cavity, the construction machine (1) comprising electrical wires to connect electrically the electrical power source (201), respectively the control unit (15), to the electrical rotary actuators (110, 120, 130), said electrical wires extending inside the hollow cavities.

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