Lifting module of a patient lifting system with powerful and high speed capacity

Abstract

A lifting module 100 is provided for patient lifting systems 300a, 300b. The lifting module 100 is coupled to a roller 50 of the patient lifting system. The lifting module includes: a first motor 10 configured to drive the roller 50; a second motor 20 configured to drive the roller 50; a planetary gearbox 40 connecting the first motor 10 and the second motor 20 to the roller 50, the planetary gearbox 40 being configured to transfer torque from the first motor 10 and / or the second motor 20 to the roller 50; and a variable locking mechanism 30. The locking mechanism 30 is configured to couple to the second motor 20, wherein the variable locking mechanism 30 is configured to provide controlled deceleration of the output shaft 43 of the planetary gearbox 40, depending on the movement of the patient 200.

Description

Technical Field

[0001] The present invention generally relates to patient lifting systems and components and assemblies thereof, and more particularly to lifting operators of patient treatment systems having double speed and controllable power, configured to move patients treated by the patient treatment system in a comfortable and safe manner. Background Technology

[0002] Patient transfer devices (such as patient lifts) are commonly used in hospitals and other care facilities, as well as in the homes of patients with limited mobility, to assist in the controlled movement of patients by supporting their full weight across different areas of the building (e.g., from bed to bathroom or from bed to chair). Patient lifts allow for individual movement and significantly reduce the effort required by caregivers, while helping to maintain the comfort and dignity of immobile individuals. Patient lifts can be used in acute care facilities, hospitals, long-term care facilities, nursing facilities, shelters, and homes, or any type of environment where healthcare services are provided and / or where patient care is required.

[0003] Patient lifts (also known as patient hoists) are commonly used to lift, lower, and transfer patients with disabilities or no mobility impairments. Two common types of patient lifts are strut-mounted lifts, also known as floor lifts and ceiling lifts. Floor lifts typically have a lifting assembly. The lifting assembly is mounted at the top of the strut. The strut has a wheeled base, which allows the patient lift to be moved to different locations along the ground.

[0004] For example, the lift can be pushed to position the lifting assembly and lifting components above or near the patient. The lifting components can then be lowered to receive the patient, and subsequently the lifting components and the patient can be lifted so that they can be pushed to other positions for lowering and placement.

[0005] Ceiling lifts can be used in a similar manner; however, the lifting assembly is movably engaged with a ceiling-mounted track, allowing the lifting assembly to move from one location to another around the track. A ceiling lift can be described as a motor unit that can move along a track, with flexible components attached to the lifting assembly in the form of struts. The motor unit typically includes a gearbox, battery, and control module. Ceiling lifts utilize ceiling lifting technology, employing various forms of lifting mechanisms to lift people from above. One form of ceiling lift is a lift capable of traveling on one or more tracks suspended from a ceiling or elevated structure. Such lifting systems include: fixed ceiling lifts, where the track is attached to the ceiling and the lifting assembly is directly attached to the track; and portable ceiling lifts, where the lifting assembly is removably attached to a ceiling track or a component attached to the ceiling track.

[0006] Typically, the lifting mechanism can be in the form of a strut, such as a two-point attachment strut, a three-point attachment strut, a four-point attachment strut, a five-point attachment strut, or a motorized strut. It is used to adjust the angle of the patient within the strut and to support the descent of the patient's safety harness or suspension belt from the lifting assembly on the sling or cable. The sling or cable is wound around a motorized roller to raise and lower the patient's safety harness or suspension belt.

[0007] For example, the lift can be wheeled (e.g., a floor lift) to position the lifting assembly and lifting member above or near the patient. The lifting member can then be lowered to receive the patient, and subsequently the lifting member and patient can be lifted and pushed to another position for lowering and placement. Ceiling lifts can be used in a similar manner; however, the lifting assembly is movably engaged with a ceiling-mounted track, allowing the lifting assembly to move from one position to another around the track.

[0008] A ceiling lift can be described as a motor unit that can move along rails or tracks, with flexible components attached to struts. The motor unit typically includes a gearbox, battery, and control module.

[0009] The transmission system faces many challenges. For example, it needs to be able to lift patients, maintain them at a specified height for a given period of time, and lower them. Furthermore, it needs to be able to lift and support a weight of approximately 450 kg.

[0010] To support such a large weight, a large electric motor capable of providing a large amount of torque is typically used. Such motors can even handle heavy loads. However, large motors are usually expensive and consume a lot of electricity.

[0011] To save costs and electricity, some manufacturers use smaller motors that can provide high RPM. To enable the smaller motors to support and lift higher loads, different types of transmissions are typically used to reduce RPM and increase torque.

[0012] Conventional patient lifts are designed to transfer patients at 4 cm / s, which is too slow for assisting patient rehabilitation. Some patient lifts incorporate solutions at 10 cm / s, but this is still too slow. Some patient lifts include a series of flexible actuators, which are very expensive. There are also patient lifts using modified lifting modules with dual motors and modified gearboxes, which can reach approximately 20 cm / s, but this is still not fast enough for assisting patient rehabilitation.

[0013] Studies have shown that it is beneficial to enable patients to move themselves and have devices assist them rather than lifting their full weight. While assistive devices have been used in rehabilitation facilities for years, their implementation in every hospital ward is prohibitively expensive. Existing patient transfer equipment available in hospital wards can offer additional rehabilitation capabilities that improve patient mobility. Commercial lifting devices offer versatility for both patient transfer and patient assistance, but their maximum speed of 10 cm / s is too slow for some daily activities. For example, during standing, a person's center of gravity can reach a vertical velocity of 51 cm / s, making it impossible for this system to keep up with all of the patient's movements. Therefore, the mechanical requirements for patient assistance differ significantly from those for patient transfer. For patient assistance, the device unloads a specific percentage of the patient's weight while keeping up with their movement. This means operating at high speeds and low force, where force mass (or force tracking) is important, making the system feel transparent to the user. For patient transfer, the device needs to lift the patient's full weight at a lower speed (high force) and position the patient through speed control.

[0014] Single-motor actuator technology must be very large and expensive to meet all these requirements for both operating modes. Low gear ratio motors are well-suited for weak, high-speed, and heavy masses, but they are inefficient in transfer mode, and their weight, size, and cost are detrimental to achieving the heavy mass requirements of transfer. Similar to available transfer devices, using smaller motors and increasing gear ratios limits maximum speed and increases reflective inertia and friction, thus hindering the application of force to masses.

[0015] Using a variable gear ratio allows for achieving the desired performance for both applications without overloading the motors. The system can downshift to a large reduction ratio for strong force capabilities during patient transfer and upshift to a small reduction ratio for high-speed capabilities when assisting the patient. Assistance implies applying a weight-reducing force to the patient and seamlessly following them at any speed during or immediately after their movement without needing to apply a weight-reducing force, but being able to stop their movement in case of a fall. T. Takayama et al. have used force-amplifying actuators for robotic hands that can move at high speeds and apply strong force when grasping objects. However, the range of motion under strong force becomes limited and the high-speed mode cannot be reversed, which is detrimental to force quality if used with a force controller. To overcome these problems, P. Vanich et al. designed a prosthetic hand using dual-motor actuators to maximize grip speed and grasp strength. Dual-motor actuators are an efficient solution for systems with two discrete operating points because each motor can be used at its optimal power. For example, T. Verstraten et al. proposed a jumping robot that uses a series elastic dual-motor actuator that utilizes redundant degrees of freedom to optimize the power distribution between two inputs. An important aspect of variable gear ratio systems for assistive lifting devices is the need for safe stabilization when handling patients who have fallen during the training phase. However, the transition would be uncomfortable for the patient. Summary of the Invention

[0016] This disclosure relates to a patient lift system and its components and assemblies, and more particularly, to a patient lift system for patient management (e.g., patient assistance and patient transfer).

[0017] In view of the foregoing description, one aspect of some embodiments of the present invention provides a lifting module for a patient treatment system with powerful and high-speed capabilities. More specifically, a lifting module configured to provide double the speed and variable and controllable power seeks to alleviate, mitigate, or eliminate one or more of the aforementioned defects and disadvantages in the art, alone or in any combination.

[0018] One aspect of the present invention relates to a lifting module for a patient lifting system. The lifting module is coupled to a roller of the patient lifting system. The lifting module includes: a first motor configured to drive the roller; a second motor configured to drive the roller; a planetary gearbox connecting the first and second motors to the roller, the planetary gearbox being configured to transfer torque from the first and / or second motors to the roller; and a variable locking mechanism. The locking mechanism is configured to couple to the second motor, wherein the variable locking mechanism is configured to provide controlled deceleration of the output shaft of the planetary gearbox. By utilizing the first motor, the second motor, and the variable locking mechanism, the lifting module is configured to adjust the gear ratio of the planetary gearbox in real time to ensure seamless transitions between different operating modes of the patient lifting system, regardless of the patient's movement.

[0019] In one embodiment, the operating mode includes: a high-speed operating mode, which includes a patient assistance mode; and a powerful operating mode, which includes a patient transfer mode and a transformation mode, including fall prevention and fall recovery.

[0020] In one embodiment, the lifting module includes a control system configured to synchronize the operation of the first and second motors during the transition between the different operating modes to optimize the performance of the lifting module.

[0021] In one embodiment, the first motor is connected to a first input shaft of the planetary gearbox and the second motor is connected to a second input shaft of the planetary gearbox, wherein the output shaft of the planetary gearbox is associated with a support member to move the patient.

[0022] In one embodiment, the first motor is configured as a high gear ratio motor and the second motor is configured as a low gear ratio motor.

[0023] In one embodiment, the planetary gearbox is configured to switch between a high gear ratio in a high-power operation mode and a low gear ratio in a high-speed operation mode.

[0024] In one embodiment, the lifting module is configured to allow precise control of output force and speed to control decelerated movement and enhance patient comfort and safety during transitions between the different operating modes.

[0025] In one embodiment, the variable locking mechanism is a disc brake.

[0026] In one embodiment, the roller is configured to control the vertical movement of the patient support mounting device of the patient lifting system via a load-bearing member.

[0027] In one embodiment, the load-bearing member is either a lifting sling or a cable, which can extend or retract as the drum rotates.

[0028] In one embodiment, the patient lift system is either a ceiling-based patient lift system or a floor-based patient lift system.

[0029] The features of the above embodiments can be combined in any combination.

[0030] Some embodiments of the invention offer the advantage of allowing for patient rehabilitation while also enabling patient transfer. This is achieved through dual-motor actuators, a lifting module, wherein a planetary differential gearbox and a variable locking mechanism are configured to control which motor supplies power to the gearbox output and thus provide seamless transitions between different operating modes. Attached Figure Description

[0032] Further objects, features, and advantages of the present invention will become apparent from the following detailed description of the invention, wherein embodiments of the invention will be described in more detail with reference to the accompanying drawings, wherein:

[0033] Figure 1a It is a ceiling-based patient lifting system according to one aspect of this disclosure.

[0034] Figure 1b It is a floor-based patient lifting system according to one aspect of this disclosure.

[0035] Figure 2a Figure b is an overview diagram of the lifting module with three operating modes according to one aspect of this disclosure.

[0036] Figure 3 This describes the operation point mapping according to one aspect of this disclosure.

[0037] Figure 4 This describes a system model based on one aspect of the present disclosure.

[0038] Figure 5 This describes the gear topology scheme based on this disclosure.

[0039] Figure 6 This describes a pattern state machine based on one aspect of this disclosure.

[0040] Figure 7 a to e illustrate the control architecture and force controller according to aspects of this disclosure.

[0041] Figure 8 This demonstrates a contribution algorithm based on one aspect of this disclosure.

[0042] Figure 9The following is a descent sequence of output speed, motor speed contribution, output force, servo angle, and output position according to one aspect of this disclosure. Detailed Implementation

[0043] Embodiments of the invention will be described more fully below with reference to the accompanying drawings, which illustrate embodiments of the invention. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make this disclosure thorough and complete and to fully convey the scope of the invention to those skilled in the art. Throughout the text, similar reference numerals refer to similar components.

[0044] For the purposes described below, the terms “up,” “down,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” “lateral,” “longitudinal,” and their derivatives should be associated with the orientation of the invention in the figures. However, it should be understood that alternative variations and sequences of steps are contemplated unless explicitly specified otherwise. It should also be understood that the specific systems and processes described in the accompanying drawings and the following description are merely exemplary examples of the invention. Therefore, specific dimensions and other physical characteristics associated with the examples disclosed herein should not be considered limiting.

[0045] This application relates to the use of Figure 1a and 1b The application shows a lifting module 100 for patient lifting systems 300a and 300b (e.g., a ceiling-based patient lifting system 300a or a floor-based patient lifting system 300b). This application further relates to systems for assisting and transferring people. In an exemplary embodiment, this application relates to a patient lifting system comprising a patient lifting assembly 310 and a patient lifting support 320, i.e., a patient suspension strap, removably attached to a patient support mounting device 330.

[0046] In one embodiment, the patient lifting assembly 310 includes wheels that engage with a track 350 mounted on the ceiling. The patient lifting assembly 310 includes a lifting module 100 configured to operate the patient lifting assembly 310 to lift and lower an individual 200, i.e., the patient. Various types of lifting assemblies exist for use based on the condition and weight of the individual to be lifted or lowered.

[0047] refer to Figure 1a and 1b The system provides a patient lifting assembly 310 that raises and lowers the patient lifting support 320. The patient lifting assembly 310 includes a lifting module 100 for winding and unfolding a flexible support member 51. The lifting module 100 is connected to a roller 50 on which the flexible support member 51 is wound.

[0048] A patient support mounting device 330, connected to and positioned below the patient lifting assembly 310, includes or is configured to connect to the patient lifting support 320 or a transport vehicle. For example, the patient lifting support 320 or the transport vehicle is a suspension strap, safety belt, basket, or the like. The patient support mounting device 330 includes a lifting rod or strut or mounting blocks for supporting the patient lifting support 320 or the transport vehicle. The patient lifting systems 300a, 300b and / or their components are powered and can also generate, use, and / or transmit data via, for example, visual displays, sensors, sound-generating components, controls, and the like.

[0049] The flexible load-bearing member 51 is a sling, cable, or the like and is formed of webbing, mesh, braided cable, layered cable, and the like, wherein power and / or data lines are defined as strands or layers. The flexible load-bearing member 51 is load-bearing and includes integrated power and / or data communication lines, such as optical transmitters, power conductors, data or signal conductors, and the like, which transmit power and / or data along the length of the load-bearing member 51. In one example, the load-bearing assembly, communication, and power transmission assembly are integrated with the flexible load-bearing member 51. The flexible load-bearing member 51 is positioned between the patient lifting assembly 310 and the patient support mounting device 330, and if configured in this way, power and / or communication are transmitted between the patient lifting assembly 310 and the patient support mounting device 330.

[0050] As described above, in the exemplary embodiment, the ceiling-based patient lift system 300a is configured as follows: Figure 1a The image shows a fixed ceiling lift and a portable ceiling lift. The ceiling patient lift system 300a includes a track 350, a receiving module (not shown), a patient lifting assembly 310, a flexible load-bearing member 51, and a patient support mounting device 330. In one aspect, the patient support mounting device 330 includes a strut with an attachment assembly 360 or other components attached to the patient lift support 320 and / or a transport vehicle. The strut 330 is moved vertically by retracting a rope 51 to lift, for example, a patient 200 from a bed, chair, wheelchair, or similar. The lifting assembly 310, having the rope 51 and the strut 330 (and therefore the patient suspension belt 320), moves horizontally to move the patient 200 from one location to another. The patient lift system 300a is used to transport a patient 200 to a desired location using the suspension belt 320 connected to the strut 330 as a transport vehicle.

[0051] As described above, in the exemplary embodiment, the floor-based patient lifting system 300b is configured as a floor lift, such as... Figure 1bAs shown in the figure. The floor lift 300b includes a lifting rod 370, a base frame 380, and a patient lifting assembly 310, i.e., a lifting arm 390. The lifting rod 370 is arranged and connected to the base frame 380. The base frame 380 may be equipped with casters or wheels for moving or transporting the floor lift. The lifting arm 310 is movably arranged with the lifting rod 370 and is used to raise and lower the lifting arm 310 to a desired position for lifting and / or transporting or supporting a patient via the lifting arm 310. The patient may be positioned in a patient lifting support 320 (i.e., a suspension strap (not shown) arranged from the lifting arm 310). In addition, the floor lift 300b includes a flexible load-bearing member 51 and a patient support mounting device 330 (not shown) coupled to a connection unit 340. In one aspect, the patient support mounting device 330 includes a strut having an attachment assembly 360 or other members attached to the patient lifting support 320. The strut 330 moves vertically by retracting the rope 51 to lift the patient 200, for example, from a bed, chair, wheelchair, or similar. The lifting assembly 310, having the rope 51 and strut 330 (and thus the patient suspension belt 320), moves horizontally to move the patient 200 from one position to another. The patient lifting system 300b is used to transport the patient 200 to a desired location using the suspension belt 320 connected to the strut 330 as a transport vehicle.

[0052] The present invention relates to a multifunctional patient lifting system 300a, 300b, which includes a lifting module 100, namely, a dual-motor actuator, which extends the capabilities of current healthcare lifting devices to the capabilities of current assistive devices with almost no compromise on system quality, efficiency and cost.

[0053] A dual-motor actuator is an actuator that uses two motors to provide precise control and increased power for moving or controlling a mechanism. A dual-motor actuator is equipped with two motors that can operate collaboratively or independently, depending on the design and application. The motors are synchronized to ensure smooth and coordinated movement. This synchronization can be achieved through an electronic control system that manages the speed and position of each motor. By using two motors, the actuator can distribute the load more evenly, thereby reducing strain on each motor and improving the overall efficiency and lifespan of the system. In some designs, a dual-motor setup provides redundancy. If one motor fails, the other can continue operating, ensuring the actuator remains operational. Using two motors allows for finer control of movement, which is particularly useful in applications requiring high precision.

[0054] refer to Figure 2a Section c demonstrates the dual-motor actuator 100 under three operating conditions of the system. Figure 2a Showing patient transfer, Figure 2b Demonstrating patient assistance, and Figure 2cDemonstrates fall prevention. Patient lift systems 300a and 300b provide enhanced control for the dual-motor actuator 100, where a variable locking mechanism 30 (i.e., brake) allows for seamless transitions between operating conditions at high speeds and with force. The dual-motor actuator 100 is configured for medical equipment used for patient transfer and patient assistance. A force control friction compensation algorithm is provided, utilizing two motors 10 and 20 to improve performance compared to a single-motor solution.

[0055] The dual-motor actuator 100 enhances the patient lifting systems 300a and 300b in several ways, for example, by utilizing two motors, the dual-motor actuator 100 can switch between different gear ratios and thus provide a variable gear ratio solution. This allows it to operate in a high gear ratio mode for high-power high-frequency (HF) applications (such as lifting or transferring patients) and in a low gear ratio mode for high-speed low-frequency (HS) applications to assist the patient.

[0056] The dual-motor actuator 100 also provides precise control over the actuator's output force and speed. This precision helps control the patient's deceleration during transitions between HS and HF, thereby reducing the risk of sudden movements that could lead to discomfort or injury. Therefore, the dual-motor actuator of this disclosure provides improved comfort and safety.

[0057] Furthermore, the dual-motor actuator 100 disclosed herein provides enhanced control during transitions. The actuator's ability to adjust the gear ratio in real time ensures seamless transitions between different operating modes, such as from patient assistance to patient transfer. This is particularly important for fall prevention and fall recovery, where controlled movement is crucial.

[0058] The synchronization process between the two motors 10 and 20 in the dual-motor actuator 100 involves several key steps to ensure smooth and efficient operation. The dual-motor actuator 100 is equipped with... Figure 4 The control system 60 shown manages the operation of two motors 10 and 20. This control system 60 is responsible for coordinating the motor actions to achieve the desired output.

[0059] Sensors and feedback mechanisms continuously monitor the performance of each motor 10, 20. This includes tracking parameters such as speed, torque, current, and position. The planetary output shaft 43 includes a torque sensing sensor (not shown), and the load-bearing member 51 includes a force sensing sensor (not shown). The control system 60 processes data from the sensors to determine the current state of the dual-motor actuator 100 and the necessary adjustments. This involves complex algorithms that calculate the optimal gear ratio and motor output required for a specific task. Based on the processed data, the control system 60 sends precise commands to each motor 10, 20. These commands ensure that the motors work in coordination, adjusting their speed and torque to maintain the desired gear ratio and output. As the patient lifting systems 300a, 300b operate, the control system 60 continuously adapts to changes in load, movement, and other variables. This real-time adjustment helps maintain smooth and controlled operation, especially during mode transitions. The dual-motor actuator 100 operates in a closed-loop configuration, where the output torque of the planetary output shaft 43, or the force applied to the load-bearing member 51, is continuously fed back to the control system 60. This feedback loop allows for immediate correction and fine-tuning, ensuring that motors 10 and 20 remain synchronized and that the dual-motor actuator 100 performs optimally. In one aspect, the lifting module 100 can also operate under open-loop force control, wherein motor current values ​​are commanded to the first and second motors 10 and 20 to obtain the desired torque at the planetary output shaft 43 or the force on the load-bearing member 51.

[0060] By synchronizing the two motors 10 and 20 in this manner, the dual-motor actuator 100 can provide precise control over the movement of the patient lifting systems 300a and 300b, thereby enhancing both the safety and comfort of the patient 200 during patient care.

[0061] In addition, the dual-motor actuator 100 includes a feedback mechanism that monitors the patient's movements and adjusts the gear ratio accordingly. This real-time adjustment helps maintain a consistent and comfortable experience for the patient.

[0062] In summary, the dual-motor actuator 100 significantly improves the functionality and reliability of the patient treatment device, making it safer and more comfortable for patients to use.

[0063] Figure 3 The mapping of operating points with these operating conditions is shown on the force-velocity diagram. The objective requirements are described below.

[0064] Figure 2a The patient transfer mode shown is for lifting patients weighing up to 272 kg (600 lb) at 4 cm / s (107 W). This is consistent with the range requirements of typical patient lift systems 300a and 300b, which can lift patients weighing between 200 and 450 kg at speeds between 3 and 5 cm / s. Patient safety and precise manipulation limit the desired speed in this mode.

[0065] Figure 2b The patient-assist mode shown is designed to assist the patient's muscles during daily activities. It is set to 50 kgf (100 kgf peak) at 50 cm / s (nominal 245 W, peak 490 W). This corresponds to 27% of the heaviest user weight that can be transferred by the dynamic unloading patient lifting systems 300a and 300b. The speed is sufficient to keep up with standing. Current patient-assist devices can unload up to 100 kg of weight quickly enough for the patient to keep up with their daily activities. Force mass is also important in this mode. A 5% tracking error is designed so that the patient does not feel any force changes.

[0066] Figure 2c The fall prevention mode demonstrated is designed to ensure that patients remain safely and comfortably still in the event of a fall during the training phase. Because the system is fast, reversible, and cannot lift heavy patients in assistive mode, injury could occur if a patient falls. The system must then detect the fall and transition to patient transfer mode at high speed. Based on the height between the knee and the ground, the maximum acceptable transition height is set at 0.4 m. Furthermore, a speed of 1 m / s is set for comfortable fall transitions. 2 Maximum acceleration, because it depends on the patient's acceleration. Studies have shown that discomfort begins at 1 m / s². 2 The acceleration is tolerable up to 2 m / s². 2 .

[0067] The mechanical principle of the dual-motor actuator 100 is described through simplified comparisons to demonstrate how this design outperforms more typical design strategies used to achieve the same function. Next, the equations of motion are detailed. Finally, the practical specifications of the dual-motor patient lifting system are detailed.

[0068] refer to Figure 4 The mechanical principle behind the dual-motor actuator 100 architecture consists of the first and second motors 10 and 20, the variable locking mechanism 30, and the planetary gearbox 40.

[0069] A planetary gearbox 40 (also known as a planetary gear train) is a complex gear system consisting of four main components: a sun gear 40a, a central gear around which the other gears rotate, planetary gears 40b, and multiple gears rotating around the sun gear. These are mounted on a movable arm called a planetary carrier 40c and a ring gear 40d (an external gear with internal teeth that mesh with the planetary gears). The sun gear 40a is positioned at the center and drives the surrounding planetary gears 40b. The planetary gears 40b are mounted on the rotating carrier 40c, which also allows them to rotate around the sun gear 40a. The ring gear 40d surrounds and meshes with the planetary gears 40b. Different gear ratios and directions of rotation are achieved by keeping one of these components stationary. For example, if the sun gear 40a remains stationary, the planetary gears 40b will rotate around it and drive the ring gear 40d, resulting in a decrease in speed but an increase in torque. Planetary gearboxes or gear trains 40 are widely used in a variety of applications due to their compact size, high efficiency, and ability to handle high torque loads. They are commonly found in automatic transmissions, electric vehicles, and industrial machinery.

[0070] Planetary gearboxes offer several advantages, making them a popular choice for a wide range of applications. They are more compact than traditional gear systems, allowing for smaller overall size and weight. High efficiency is provided due to load distribution among multiple gears, reducing stress on individual gears. These gearboxes can handle high torque loads, making them suitable for heavy-duty applications. They offer a wide range of gear ratios and can be easily switched between different operating modes (e.g., forward, reverse, and neutral). The design of planetary gearboxes results in smooth and quiet operation with reduced vibration and noise. The load-sharing capability among the planetary gears enhances the durability and lifespan of the gear train.

[0071] refer to Figure 4 The first motor 10 is a high gear ratio motor, while the second motor 20 is a low gear ratio motor. The outputs of the first and second motors 41 and 42 are connected to a planetary gearbox 40. The output shaft 43 of the planetary gearbox 40 connects the roller 50 to the planetary carrier 40c. At the output of the roller, the carrier member 51 is attached to the patient 200. The planetary gearbox 40 thus functions as a differential device. This results in a redundant system, where the displacement of each motor is summed to drive the output.

[0072] refer to Figure 6This architecture features two operating modes: High Force Mode (HF) and High Speed ​​Mode (HS). In HF mode 410, the variable locking mechanism 30 is closed and the first motor 10 drives the planetary output shaft 43, resulting in slow displacement but providing strong force capability. In HS mode 420, the variable locking mechanism 30 is open and the second motor 20 drives the planetary output shaft 43, resulting in high speed capability and low reflective inertia, which is beneficial for assisting patients during daily activities requiring rapid movement. Controlling the sliding of the variable locking mechanism ensures seamless transitions between the two control modes of the system through high power consumption capability (i.e., high speed and strong force). This provides even greater flexibility in meeting the requirements of patient transfer and assistance. For example, when a patient falls at high speed, the system needs to apply strong force to restrain the patient.

[0073] In one embodiment, a lifting module 100 is provided for patient lifting systems 300a, 300b. The lifting module 100 is coupled to a roller 50 of the patient lifting system. The lifting module includes: a first motor 10 configured to drive the roller 50; a second motor 20 configured to drive the roller 50; a planetary gearbox 40 connecting the first motor 10 and the second motor 20 to the roller 50, the planetary gearbox 40 being configured to transfer torque from the first motor 10 and / or the second motor 20 to the roller 50; and a variable locking mechanism 30. The locking mechanism 30 is configured to couple to the second motor 20, wherein the variable locking mechanism 30 is configured to provide controlled deceleration of the output shaft 43 of the planetary gearbox 40, depending on the movement of the patient 200. This is achieved by utilizing the first motor 10, the second motor 20, and the variable locking mechanism 30. The lifting module 100 is configured to adjust the gear ratio of the planetary gearbox 40 in real time to ensure seamless transitions between different operating modes of the patient lifting system, regardless of the movement of the patient 200.

[0074] In one aspect, the variable locking mechanism 30 is configured to provide controlled deceleration of the second motor 20 to prevent falls and to provide assistance during patient movement.

[0075] In one embodiment, in HS auxiliary mode 420, the first and second motors 10 and 20 operate together at high speed. This results in the total speed being added together.

[0076] In one embodiment, in HF transfer mode 410, the first motor 10 is operational and the variable locking mechanism 30 is applied to the second motor 20.

[0077] In one embodiment, in rehabilitation mode 430, the lifting speed is 50 cm / s and the assistive capacity is up to 100 kg.

[0078] In one embodiment, in transfer mode 440, the lifting speed is 4 cm / s and the lifting capacity is up to 357 kg.

[0079] Since the two motors 10 and 20 operate to drive the output 43 of the planetary gearbox 40, the kinematic equations (motion equations) of the system can be simplified using the lumped parameter method, which leads to:

[0080]

[0081] Where v0 is the linear velocity of the output sling 43, and ω1 and ω2 are the angular velocities of the high-gear-ratio motor 10 and the low-gear-ratio motor 20. Assume the radius r of the drum 50 is constant, and R1 and R2 are the gear ratios between each motor and the output of the drum 50, including any gear ratios of the drum, planetary gearbox 40, and motor gearbox. The static relationship is:

[0082]

[0083] Where F m This indicates the output force on the roller. and This indicates the motor torque of the first motor 10 and the second motor 20. This refers to the frictional torque of the brake. When considering the system's inertia, a 2-DOF state-space model can be constructed, where the states are v0 and ω1:

[0084] ,in:

[0085]

[0086]

[0087] Where m is the load on the bearing member 51 and includes the inertia of the roller 50, and I1 and I2 are the inertia of the first and second motors 10 and 20. b0, b1 and b2 represent the viscous friction of the output of the first motor 41 and the output of the second motor 42.

[0088] In HF mode, the variable locking mechanism 30 is fully closed and only the first motor 10 can drive the output of the planetary gearbox 43. Therefore, the equations can be simplified to a single-motor, single-output system:

[0089]

[0090] In HS mode, the two motors 10 and 20 can drive the motion of the planetary output 43. However, since the first motor 10 has a greater mechanical advantage than the second motor 20, when When the equations are simplified, this is the case when designing a prototype:

[0091]

[0092] Therefore, the effect of the first motor 10 in HS mode mainly comes from kinematic equation 1 and can be used to offset the output speed. In summary, the equations for both modes have the same structure, and the difference arises from the relationship between the mechanical advantages of I1 and I2.

[0093] Figure 5 An embodiment of a dual-motor actuator 100 for a patient lifting system 300a, 300b comprising a wound support member 51 and a roller 50 is shown. A first motor 10 (i.e., Maxon RE40 150 W) with an integrated gearbox of 66:1 is coupled to the ring gear 40d of a planetary gearbox 40. A second motor 20 (i.e., Tecnotion QTR-A-78-25) is directly coupled to the sun gear 40a of the planetary gearbox 40. The planetary gearbox 40 also includes planetary gear stages 40b. In one aspect, the overall reduction ratios for the first motor 10 and the second motor 20 are R1 = 600:1 and R2 = 18:1, respectively. A planetary output shaft 43 is connected to the roller 50 (average 4 cm radius r). Encoders are implemented on both motors 10, 20, and load cells measure the load applied to the support member 51. The variable locking mechanism 30 is coupled to the second motor 20 to variably control the locking mechanism from being reverse-driven by the first motor 10 during HF mode and fall-prevention mode. In one aspect, the variable locking mechanism 30 is a disc brake and is made of carbon fiber to minimize reflective inertia in HS mode.

[0094] In one embodiment, in HF mode, the load is limited by the rated torque of the 66:1 gearbox. In HS mode, peak force is reached when the sending motor's nominal current is twice that of the sending motor.

[0095] Figure 6 A state machine 400 is demonstrated, comprising a patient transfer device 410 with strong high-frequency haptic (HF) capability, a patient assistance device 420 with high-speed high-speed haptic (HS) capability, a fall prevention device 440 for catching the patient during a fall, and a fall recovery device 430 for lifting the patient after a fall. The main operating mode can be manually changed between strong HF mode and high-speed HS mode, such as... Figure 6 As shown in the diagram. If the patient is about to fall, the patient lift systems 300a and 300b also need to automatically switch from HS mode to HF mode (fall prevention) to support the patient's full weight and prevent the fall (fall recovery).

[0096] The transition between HF and HS modes is achieved by smoothly and seamlessly opening or closing the variable locking mechanism 30. If a fall is detected in HS mode, the variable locking mechanism 30 and the second motor 20 operate simultaneously to decelerate the patient before downshifting. The first motor 10 applies downward velocity to facilitate faster downshifting. Once the second motor 20 reaches zero velocity, the variable locking mechanism 30 approaches its maximum braking force, and the patient lifting systems 300a and 300b switch to HF mode. To help the patient recover and continue their activities, the patient lifting systems 300a and 300b then lift them back to the position where the fall was detected. Each operating mode is further explained below:

[0097] - Patient transfer pattern 410:

[0098] To transfer patient 200, patient lifting systems 300a and 300b need to lift the full weight of patient 200. This requires patient lifting systems 300a and 300b to be in HF mode utilizing a first motor 10 with a high gear ratio. The controller sends speed commands to the first motor 10 based on user up / down input on the remote control. This is the basic functionality of currently available patient lifts.

[0099] - Patient Assistance Mode 420:

[0100] To assist patient 200 in daily activities, patient lifting systems 300a and 300b need to unload a certain amount of patient 200's weight while keeping up with their movement. This requires patient lifting systems 300a and 300b to be in HS mode and control the force at the output, rather than controlling position or speed as in transfer mode. The force control algorithm 500... Figure 7 Presented in sections a through e. Figure 7 a demonstrates open-loop current control. Figure 7 b demonstrates the friction compensation algorithm. Figure 7 c demonstrates a friction compensation algorithm with a velocity offset. Figure 7 d shows the PID current controller, and Figure 7 e shows the Disturbance Observer (DOB).

[0101] Motor torque is obtained by knowing the motor constant (k) t This is achieved by adjusting the current of the second motor 20. Figure 7 As shown in section a. This is well-suited for low gear ratio motors, but friction can induce undesirable errors in force output. This error can be measured using speed. Dry and viscous friction models can be estimated using a linear equation (using the absolute value of symmetry) multiplied by a hyperbolic tangent function:

[0102]

[0103] Next, the friction estimate can be subtracted from the expected force to compensate for friction errors and help improve force quality, such as... Figure 7 As shown in b. One problem with friction compensation is when to attempt to compensate for speeds close to zero, as a more complex friction model would be needed to account for hysteresis. Through dual-motor actuators 100, the first motor 10 can operate at a constant speed, while the second motor 20 applies a constant force, such as... Figure 7 As shown in c. This causes the speed of the second motor 20 to deviate from the output speed, which reduces the time the second motor 20 is at zero speed, since the patient 200 is typically close to zero speed (when standing still or sitting). In one embodiment, force fidelity in the rehabilitation mode (i.e., fall recovery mode) is improved by using the second motor 20 to offset the speed of the first motor 10 to avoid near-zero speed stick-slip behavior. In one aspect, a weighing sensor is required on the patient lifting system 300a, 300b to measure the patient's weight, and the measured force can be sent to a simple closed-loop PID controller, such as... Figure 7 As shown in d. The disturbance observer is implemented to compare different, more refined control laws, such as... Figure 7 Displayed in e.

[0104] - Fall Prevention 440 and Fall Recovery 430: The fall prevention algorithm has two objectives: first, to safely and comfortably prevent the patient 200 from falling; second, to help the patient 200 resume their subsequent daily activities. To ensure the patient's safety, the patient lifting systems 300a and 300b must ensure that the patient 200 never touches the ground during a fall. Regarding comfort, this depends on the patient's acceleration. To apply the desired deceleration (v'0) to the patient 200, the torque required by the variable locking mechanism 30 can be calculated knowing the patient 200's weight, see [link to relevant documentation]. Figure 8 Equation 9 is shown in the diagram. The variable locking mechanism 30 is controlled by a servo motor (not shown), thus the variable locking mechanism 30 can apply only discrete amounts of force and introduce a specific delay when the servo motor moves to the desired angle. To improve the accuracy and response time of the patient lifting systems 300a, 300b, the second motor 20 applies torque proportional to the error in the desired speed. Figure 8 The contribution algorithm 600 shown is used by the second motor 20 during the fall prevention 440.

[0105] Figure 9 This demonstrates a complete descent sequence with output speed V0, speed contributions W2r / R2 and W1r / R1 of the first and second motors 10 and 20, output force, servo angle, output position, and height, at 2 m / s. 2In this case, the weight is 90 kg. Starting from a height of 1 m, the weight begins to descend at (a) until it reaches 90 cm / s (b), at which point the system detects a fall and moves the variable locking mechanism 30 to obtain the desired braking force. To assist in faster downshifting, the first motor 10 applies its maximum downward speed when a fall is detected. Once the speed of the second motor 20 reaches 2 cm / s (c), the variable locking mechanism 30 fully locks to transfer control to the first motor 10, which can then complete deceleration at a constant rate until the fall is completely stopped (d). The first motor 10 then lifts the patient 200 to the height at which the fall was detected (e) to help the patient stand and continue their activities.

[0106] The fall distance *x* can be calculated by measuring the height at the moment of fall and the lowest point. The average acceleration during the fall is represented by... Calculate, where v i The measured mass velocity at the time of the fall is the average force, calculated using F = m(g + a). Acceleration is a tuned parameter related to patient comfort. Fall distance is more intuitive and relevant to patient safety, as it indicates the minimum fall distance required by the patient. The force roughly corresponds to the braking capacity of the patient lift systems 300a and 300b.

[0107] At the start of the braking sequence, only the second motor 20 applies torque to slow the mass. Since the second motor 20 can only lift a maximum of 59 kgf, its contribution is more significant relative to the patient's weight when the patient's mass is low, and the patient lifting systems 300a and 300b can apply the desired braking torque from the outset. This means that the patient lifting systems 300a and 300b can decelerate the mass over a shorter distance. As the mass increases, the effect of the second motor 20 decreases, and the patient lifting systems 300a and 300b require a longer distance to brake the patient. For patients weighing less than 90 kg, the patient lifting systems 300a and 300b can comfortably (at 1 m / s²) slow the mass. 2 And safely (at a height of less than 40 cm) brake the patient from falling. For more seriously injured patients, the patient lift systems 300a and 300b need to brake with a higher deceleration value to ensure patient safety.

[0108] In one embodiment, the variable locking mechanism 30 and control scheme allow for a “downshift” to a transfer mode (e.g., to catch a patient who has fallen), regardless of any speed / external force at the system output.

[0109] In one embodiment, patient lifting systems 300a and 300b are provided capable of patient transfer, patient assistance, and fall prevention using dual-motor actuators 100. Patient lifting systems 300a and 300b are configured to lift a patient weighing up to 318 kg at 4.6 cm / s during transfer mode 410 and unload a patient weighing up to 59 kg at a maximum speed of 55 cm / s during assistance mode 420. Using a friction compensation algorithm and utilizing two motors 10 and 20, the force tracking error during patient assistance mode is 12% at high speed and 7.8% at low speed, similar to the performance of a conventional closed-loop controller. For the fall prevention algorithm 440, the patient's deceleration can be controlled to dissipate energy by applying a desired amount of force using a variable locking mechanism 30.

[0110] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a” and “described” are also intended to include the plural forms unless the context clearly indicates otherwise. It should be further understood that the terms “comprising” and / or “including” as used herein specifically mean the presence of the stated feature, integer, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0111] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should be further understood that the terms used herein shall be interpreted to have the same meaning as in the context of this specification and related fields, and shall not be interpreted in an idealized or overly formal sense, unless expressly defined herein.

[0112] The principles, preferred embodiments, and operating modes of the present invention have been described above. However, the present invention should be considered illustrative rather than restrictive and should not be limited to the specific embodiments discussed above. Different features of various embodiments of the present invention can be combined in combinations other than those explicitly described. Therefore, it should be understood that variations can be made to these embodiments by those skilled in the art without departing from the scope of the invention as defined by the appended claims.

[0113] Reference element symbol

[0114]

[0115]

Claims

1. A lifting module (100) for a patient lifting system (300a, 300b), the lifting module (100) being coupled to a roller (50) of the patient lifting system, wherein the lifting module comprises: - A first motor (10), configured to drive the roller (50), - A second motor (20), configured to drive the roller (50), - A planetary gearbox (40) connecting the first motor (10) and the second motor (20) to the roller (50), the planetary gearbox (40) being configured to transfer torque from the first motor (10) and / or the second motor (20) to the roller (50), and - Variable locking mechanism (30), The locking mechanism (30) is configured to couple to the second motor (20), and the variable locking mechanism (30) is configured to provide controlled deceleration of the output shaft (43) of the planetary gearbox (40). By utilizing the first motor (10), the second motor (20), and the variable locking mechanism (30), the lifting module (100) is configured to adjust the gear ratio of the planetary gearbox (40) in real time to ensure seamless transitions between different operating modes (HS, HF, 410, 420, 430, 440) of the patient lifting system, regardless of the movement of the patient (200).

2. The lifting module (100) according to claim 1, wherein the operation mode includes: high-speed operation mode (HS), which includes patient assistance mode (420); strong operation mode (HF), which includes patient transfer mode (410) and conversion mode, including fall prevention (440) and fall recovery (430).

3. The lifting module (100) according to claim 2, comprising a control system (60) configured to synchronize the operation of the first and second motors (10, 20) during the transition between the different operating modes (HS, HF, 410, 420, 430, 440) to optimize the performance of the lifting module (100).

4. The lifting module according to claim 1, wherein the first motor (10) is connected to the first input shaft (41) of the planetary gearbox (40) and the second motor (20) is connected to the second input shaft (42) of the planetary gearbox, and wherein the output shaft (43) of the planetary gearbox is associated with a support member (51) for moving the patient (200).

5. The lifting module (100) according to claim 1, wherein the first motor (10) is configured as a high gear ratio motor and the second motor (20) is configured as a low gear ratio motor.

6. The lifting module (100) according to claim 1, wherein the planetary gearbox (40) is configured to switch between a high gear ratio in a high-power operation mode and a low gear ratio in a high-speed operation mode.

7. The lifting module (100) according to claim 1, wherein the lifting module (100) is configured to allow precise control of output force and speed to control deceleration movement and to enhance patient comfort and safety during transitions between the different operating modes (HS, HF, 410, 420, 430, 440).

8. The lifting module (100) according to claim 1, wherein the variable locking mechanism (30) is a disc brake.

9. The lifting module (100) according to claim 1, wherein the roller (50) is configured to control the vertical movement of the patient support mounting device (330) of the patient lifting system (300a, 300b) via a support member (51).

10. The lifting module (100) according to claim 9, wherein the supporting member (51) is either a lifting sling or a cable that can extend or retract as the drum rotates.

11. The lifting module according to any one of claims 1 to 10, wherein the patient lifting system is either a ceiling-based patient lifting system (300a) or a floor-based patient lifting system (300b).

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