Sensor arrangement for a human-powered vehicle, drive train and vehicle with a sensor arrangement

Abstract

A sensor arrangement (1) for a muscle-powered vehicle (2) is described. The sensor arrangement (1) has a pedal crankshaft (4), a bearing (6) by means of which the pedal crankshaft (4) is rotatably mounted on a frame (10) of the vehicle (2), and at least three force sensors (8a, 8b, 8c), each of which is designed to detect a radial force acting from the pedal crankshaft (4) on the bearing (6). Furthermore, a drive train (16) for a muscle-powered vehicle (2) having such a sensor arrangement (1) and a muscle-powered vehicle (2) having such a sensor arrangement (1) are described.

Description

Technical FieldThe present invention relates to a sensor arrangement for a muscle-powered vehicle. The present invention further relates to a drive train for a muscle-powered vehicle having such a sensor arrangement. The present invention further relates to a muscle-powered vehicle having such a sensor arrangement.Prior ArtMuscle-powered vehicles are known from the prior art, which are designed to determine different measured variables on the vehicle. For such a vehicle having a drive motor for controlling the drive motor, it is often necessary or at least advantageous to determine a force applied by a driver of the vehicle to a pedal crank shaft of the vehicle. For example, DE102012022447A1 describes that a force applied by a driver to a pedal crankshaft can be determined by means of strain gauges. The strain gauges are integrated into crank arms of the bicycle, wherein the crank arms consist of fiber-reinforced plastic.SUMMARY OF THE INVENTIONIt is an object of the invention to improve a determination of an influence applied to a pedal crank shaft by a driver of a muscle-powered vehicle. This object is achieved by the subject matters of the independent claims.A first aspect relates to a sensor arrangement for a muscle-powered vehicle having a pedal crank shaft, a bearing and at least three force sensors. The muscle-powered vehicle can be, for example, a bicycle, an e-bike, a pedelec or a loadwheel. The pedal crank shaft may be a shaft of the vehicle to which pedals for introducing muscular driving force are attached. The pedal crankshaft may also be referred to as a pedal crankshaft of the vehicle. Two cranks can be connected to the crankshaft in a rotationally fixed manner. A pedal may be rotatably attached to each of the cranks. The bearing may be a bottom bracket of the vehicle. The bearing can be designed, for example, as a rolling bearing, sliding bearing or ball bearing. By means of the bearing, the pedal crankshaft can be rotatably mounted on a frame of the vehicle. The sensor arrangement can have exactly three force sensors. Alternatively, the sensor arrangement can have more than three force sensors. The three force sensors are each designed to detect a radial force acting from the pedal crankshaft on the bearing. The radial force may be a reaction force acting, for example, radially outward on the bearing. From the three or more detected radial forces, a total bearing force can be determined. Depending on the position of the three force sensors relative to the pedal crankshaft, one of the portions of the total bearing force detected by the individual force sensors may be different.With the sensor arrangement, various forces acting from the pedal crankshaft on the bearing can be detected. In this case, the force sensors can be used, for example, to detect a local effect of the support of the crankshaft on the bearing on the basis of acting radial forces, such as a deformation at different points of the bearing. By using at least three force sensors, more information about the radial forces acting from the crankshaft on the bearing can be detected. This increases an accuracy of the sensor arrangement when detecting acting radial forces from the pedal crankshaft onto the bearing. For example, in any angular position of the pedal crankshaft, it is always possible to correctly infer an overall bearing force and its direction, in contrast to, for example, using only two force sensors.According to a further embodiment, the at least three force sensors can be arranged on the bearing. For example, the force sensors can be contacted and connected to the bearing, for example, be fastened to the bearing. For example, the three force sensors can be arranged on the end face of the bearing and fastened, for example. For example, the force sensors may be disposed and attached to an outer ring of the bearing between the bearing and the frame of the vehicle. Alternatively or additionally, the force sensors can be arranged and fastened on an inner ring, for example between the bearing and the crankshaft or on the end face of the bearing. In one embodiment, at least one of the at least three force sensors may be arranged and fixed to the inner ring and at least another one of the force sensors may be arranged and fixed to the outer ring. However, all force sensors can also be arranged uniformly and alternatively or additionally fastened uniformly, for example at an identical radial distance from an axis of rotation of the pedal crankshaft and alternatively or additionally at an identical distance from one another in the circumferential direction.If, for example, at least one force sensor is fastened to the outer ring, and thus to the frame of the vehicle, a particularly simple sensor arrangement can be achieved. This is achieved, for example, by the force sensor being arranged and fastened, for example, to a non-rotating part such as the frame of the vehicle or the outer ring in such a case. A wiring to the force sensor from one location of the frame, for example from a data processing unit connected to the force sensor, can thus be realized in a simple manner.According to a further embodiment of the sensor arrangement, it can be provided that the at least three force sensors are arranged equidistantly in the circumferential direction. The pedal crankshaft can define an axis of rotation. The axis of rotation of the pedal crankshaft may be identical to an axis of rotation of the bearing. The three force sensors can be arranged equidistantly in the circumferential direction about this axis of rotation, for example at an identical radial distance from the axis of rotation. The at least three force sensors can be arranged equidistantly from one another. In the case of exactly three force sensors, the force sensors can be arranged at an angular distance of 120° in the circumferential direction. If the sensor arrangement has four force sensors, for example, the force sensors can be arranged at an angular distance of 90° in the circumferential direction. By the equidistant arrangement of the force sensors, a particularly accurate detection of the radial forces between the pedal crankshaft and the bearing can take place. In addition, calculation of the total force can be so very simple.According to a further embodiment of the sensor arrangement, it can be provided that the at least three force sensors are designed as deformation sensors. For example, a deformation sensor may be a strain gauge, a piezoelectric force sensor, or a magnetostrictive force sensor. The force sensors designed as deformation sensors can be placed particularly freely. In addition, such sensors cannot be directly subjected to a force influence by the pedal crankshaft and thus are subject to little wear.In a further embodiment, the at least three force sensors can be designed as capacitive force sensors. In one embodiment, at least one force sensor may be a deformation sensor and at least one other force sensor may be a capacitive force sensor.Furthermore, the deformation sensors, and alternatively or additionally the capacitive force sensors, can be designed to detect the respective radial force acting on the bearing on the basis of a detected deformation of the bearing. For example, the deformation of the bearing can be linearly related to the detected radial force. Alternatively, there may be another functional relationship between deformation of the bearing and acting radial force. With the force sensors mentioned, a radial force acting from the pedal crankshaft on the bearing can be detected particularly easily and cost-effectively.According to a further embodiment of the sensor arrangement, it can be provided that the sensor arrangement has a data processing unit. The data processing unit can have, for example, one or more microprocessors. The data processing unit can be configured for communication with each of the three force sensors, for example wirelessly or by wire. The data processing unit can be designed to determine a total force applied to the crankshaft by the driver of the vehicle as a function of the detected radial forces. For example, the total force can be determined in absolute value and alternatively or additionally in the direction. For example, the determination of the total force can be carried out by summing some or alternatively all detected radial forces. The sensor arrangement can therefore be used to determine the total force applied to pedals by a driver of the vehicle in a particularly simple manner. This determined total force can be used, for example, for motor control of a pedelec.Furthermore, the data processing unit can be designed to determine a driving state. For example, as the driving state, it can be determined that the driver pedals while being seated or that the driver pedals while standing and performs a swing pedal operation. Such a driving state can be determined as a function of the detected radial forces. Because the sensor arrangement has at least three force sensors, a virtually constant detection performance can be achieved over a complete crank rotation, in that the radial forces can be determined with a plurality of force sensors and the total force can be determined virtually or even completely uniformly over a crank rotation. The determination of the total force can thus be possible independently of a specific angular position of the crankshaft.According to a further embodiment of the sensor arrangement, it can be provided that the sensor arrangement further comprises a means for determining an angular position of the pedal crankshaft. For example, the means which can be designed to determine the angular position can be used to determine an angular position of the pedal crankshaft, for example relative to the frame of the vehicle. An angular position may be an orientation of the crankshaft relative to the bearing. The angular position of the pedal crank shaft can correspond, for example, to a position of the pedals and crank arms.According to a further embodiment of the sensor arrangement, it can be provided that the means for determining the angular position of the pedal crankshaft can be an angle sensor. The angle sensor can be arranged, for example, on the pedal crankshaft; alternatively, the angle sensor can be arranged on the frame of the vehicle or on the bearing. The angle sensor can be configured to determine an angle between a rotationally fixed component of the vehicle, such as the frame, and a component mounted rotatably with respect to the frame, such as the pedal crank shaft. The determination with the angle sensor may be a measurement. With such a means for determining the angular position, the angular position of the crankshaft can be determined particularly easily and accurately. As a result, it is also possible to verify forces and angular positions determined on the basis of the detected radial forces or to dispense with a determination of the angular position on the basis of the detected radial forces.According to a further embodiment of the sensor arrangement, it can be provided that the means for determining the angular position of the pedal crankshaft can be the data processing unit. The sensor arrangement can have both the angle sensor and the data processing unit for determining the angular position of the pedal crankshaft. Alternatively, the sensor arrangement can have exactly one of the two means, either the angle sensor or the data processing unit, for determining the angular position of the pedal crankshaft. If the sensor arrangement has only one means for determining the angular position, the determination of the angular position can be carried out particularly quickly, simply and cost-effectively. If the sensor arrangement for determining the angular position has both means, the determination of the angular position can be carried out particularly accurately, for example by a comparison between the angular position determined with the angle sensor and the angular position determined with the data processing unit.The data processing unit can be designed to determine the angular position of the pedal crankshaft as a function of the detected radial forces. For example, the data processing unit can be designed to determine the angular position as a function of some or all detected radial forces. Thus, depending on which force sensor arranged along the circumferential direction has detected a specific radial force, the angular position of the pedal crankshaft can be determined. For example, a first force sensor is arranged to be disposed at a 12 o'clock position relative to the frame. A second of the, for example, exactly three force sensors is arranged, for example, at a 4-o'clock position, and a third at an 8-o'clock position. If the detected radial forces of the first force sensor are, for example, greater than those of the third and second force sensors, a position between the 10 o'clock position and the 2 o'clock position of the crank relative to the frame of the vehicle is, for example, determined as the angular position of the crank shaft for one of the pedals, wherein an exact position can also be determinable as a function of the relative magnitudes of the forces. On the basis of a profile and alternatively or additionally on the basis of further assumptions, for example that a front pedal is usually pressed more strongly, it is then also possible to determine an exact angular position of the pedal crankshaft and its crank arms.According to a further embodiment of the sensor arrangement, it can be provided that the data processing unit is designed to determine a driver torque on the crankshaft as a function of the detected radial forces and as a function of the determined angular position of the crankshaft. The driver torque may be a torque applied to the pedals by the driver of the vehicle. Alternatively or additionally, the data processing unit can be designed to determine a driver's performance, i.e. a performance applied by the driver to the pedals. For determining the driver's performance, the sensor arrangement can additionally have a means for determining a driver's coldness, i.e. a rotational speed of the pedal crankshaft. For example, the means for determining the carcass may be a carcass sensor. Alternatively or additionally, the means for determining the carcass may be the data processing unit, wherein the data processing unit may be configured to determine the carcass by means of a mathematical method as a function of the angular position of the pedal crankshaft.With such a sensor arrangement, the total force, the driving state, the driver torque and the driver power can be determined. This can lead to an improved scope of functions of the sensor arrangement, for example in combination with further devices of the vehicle.A second aspect relates to a drive train for a muscle-powered vehicle having a sensor arrangement according to one embodiment of the first aspect. Respective further features, embodiments and advantages can be gathered from the descriptions of the first aspect. Conversely, features, embodiments and advantages of the second aspect also represent features, embodiments and advantages of the first aspect.The drive train can have a control device, for example a control unit of the vehicle. The control device can be designed to control an element of the drive train as a function of the detected radial forces. The control device can be designed to control at least one element, for example exactly one element or a plurality of elements. In this case, the control can be carried out directly as a function of the detected radial forces. Alternatively, the control can be configured indirectly as a function of the detected radial forces, i.e. for example as a function of the determined total force or the determined driver torque. The control device may be configured to control one or more elements of the powertrain. For example, controlling an element of the powertrain may be performed depending on the determined driver torque. For example, a brake system can be the controlled element of the drive train. The data processing unit can be or comprise the control device. Alternatively, the data processing unit and the control device may be different devices.According to a further embodiment of the drive train, it can be provided that the element is a drive motor of the vehicle, which can be designed for driving the vehicle. The drive motor may be an electric motor. For example, the control device may be designed to control the drive motor as a function of the determined driver torque. For example, a setpoint torque of the drive motor may be determined as a multiple of the determined driver torque.According to a further embodiment of the drive train, it can be provided that the element can be a transmission of the vehicle with multiple transmission ratios and an actuator for switching between the transmission ratios. The transmission may have multiple gear stages. Alternatively, the transmission may be a continuously variable transmission, thus providing multiple gear ratios. The actuator can be designed, for example, for automatic adjustment of the transmission stages. For example, the control device can be designed to trigger gear changes as a function of the determined total force, as a function of the determined driver torque and alternatively or additionally as a function of the determined driver power. For example, a transmission ratio may be increased if the determined total force, driver torque, and alternatively or additionally driver power are below threshold values. Further, controlling the actuator to shift between ratios may be performed such that the ratio is reduced when the determined total force, driver torque, and alternatively or additionally the determined driver power exceed thresholds. If the transmission is a continuously variable transmission with a continuously variable transmission ratio, the ratio of the transmission can be regulated with the actuator. For example, the determined total force and, alternatively or additionally, the determined driver torque may be used as setpoints for controlling the transmission ratio. Thus, it can be ensured in a simple manner with the drive train that the total force to be applied by the driver, the driver torque to be applied by the driver and alternatively or additionally the driver power to be applied by the driver can be kept in a comfortable range for the driver.The control device may be designed to determine a shift time for shifting between the transmission ratios. The determination of the switching point can be carried out as a function of the detected radial forces, for example as a function of the determined total force, as a function of the determined driver torque and alternatively or additionally as a function of the determined driver power. For example, the shift between transmission ratios and thus the shift time can be determined such that the total force, the driver torque and alternatively or additionally the driver power is particularly low, for example if the two crank arms extend substantially perpendicularly. Thus, a comfortable shift between gear ratios can be achieved for the driver, and at the same time, mechanical wear of the transmission can be reduced.A third aspect relates to a muscle-powered vehicle having a sensor arrangement according to an embodiment of the first aspect. Alternatively or additionally, the muscle-powered vehicle comprises a drive train according to an embodiment of the second aspect. The muscle-powered vehicle can be, for example, a bicycle, an e-bike, a pedelec or a loadwheel. Respective further features, embodiments and advantages can be gathered from the descriptions of the first aspect and of the second aspect. Conversely, features, embodiments and advantages of the third aspect also represent features, embodiments and advantages of the first or second aspect.For example, the vehicle may include an output device. The output device can be designed to output the detected radial forces, the determined total force, the determined angular position of the crankshaft, the determined driver torque and alternatively or additionally the determined driver power. The output device can be, for example, a display on the driver of the vehicle. The display on the handlebar of the vehicle may be, for example, a cycle computer or part of the cycle computer.Alternatively or additionally, the output device can have a communication interface. The output device can be connected via the communication interface to a mobile terminal of the driver, such as a smart watch, a smart ring, a cell phone or a laptop. Furthermore, the output device can be connected to a server or to a personal computer via the communication interface. By way of the output device, for example, the detected radial forces, the determined total force, the determined angular position of the crankshaft, the determined driver torque and alternatively or additionally the determined driver power can be visualized to the driver. Alternatively or additionally, haptic or acoustic output is also possible. The vehicle may further include a storage unit, which may be configured to store the detected radial forces, the determined total force, the determined angular position of the crankshaft, the determined driver torque and alternatively or additionally the determined driver power. Thus, on the one hand, the detection of the radial forces, the determination of the total force, the determination of the angular position of the crankshaft, the determination of the driver torque and alternatively or additionally the determination of the driver power and, on the other hand, the visualization can be carried out independently of one another in time. In addition, these data are then available for later evaluation.According to a further embodiment of the muscle-powered vehicle, it can be provided that the vehicle can have at least one user interface for detecting a user input. The user interface can be, for example, an operating element of the vehicle, such as, for example, a button or a touchscreen display on the steering wheel of the vehicle. The user interface may include a communication interface for communicating with a mobile terminal, such as a handy phone, smart watch, smart ring, or wearable of the driver, whereby user inputs may be received and detected therewith. The user input can comprise, for example, information about thresholds or parameters. Such threshold values can be, for example, threshold values for controlling the actuator for shifting the transmission ratio.The control device can be configured to control the element additionally depending on the user input detected. For example, the actuator for shifting the transmission ratio can be implemented as a function of the threshold value predefined by the driver for the specific driver torque. For example, the actuator for switching can also be controlled as a function of the user input. Before the transmission ratio is shifted, information about the output device of the vehicle can be output to the driver that a shift between transmission ratios is planned. The driver can then either reject or accept this shift. Accepting the shift by the driver may trigger the shift. Control can be taught and improved by rejecting and accepting. Alternatively or additionally, the user input may include a shift command from the driver, whereby a shift may be initiated. The control can be taught and improved by the switching command. The vehicle, for example the control device, can be configured to store this user input and to use it for future control of the element, here for shifting with the actuator of the transmission.Brief Description of the FiguresFIG. 1A schematically shows elements of a sensor arrangement in a sectional view for a muscle-powered vehicle. FIG. 1B schematically shows the sensor arrangement from FIG. 1A in another sectional view. FIG. 2 schematically shows a vehicle in plan view with such a sensor arrangement.Detailed Description of EmbodimentsFIG. 1A schematically shows elements of a sensor arrangement 1 in a sectional view for a muscle-powered vehicle 2 which is configured as a bicycle. FIG. 2 schematically shows such a vehicle 2 in a plan view. The sensor arrangement 1 has a pedal crankshaft 4. The bicycle has two cranks which point in opposite directions from one another by 180° in each case and which are connected to the crankshaft 4 in a rotationally fixed manner. FIG. 1B schematically shows another sectional view of the sensor arrangement 1 with the pedal crankshaft 4 with the two pedals. Furthermore, the sensor arrangement 1 has a bearing 6. By means of the bearing 6, the pedal crankshaft 4 is rotatably mounted on a frame 10 of the vehicle 2. Furthermore, the sensor arrangement 1 has three force sensors 8 a, 8 b, 8 c. The three force sensors 8 a, 8 b, 8 care each designed to detect a radial force acting from the pedal crankshaft 4 on the bearing 6.The three force sensors 8 a, 8 b, 8 care arranged on the bearing 6. Here, the three force sensors 8 a, 8 b, 8 care arranged on an outer ring of the bearing 6 between the bearing 6 and the frame 10. In an alternative embodiment, the three force sensors 8 a, 8 b, 8 care arranged on the end face on the outer ring of the bearing 6, and the outer ring bears directly radially on the outside on the frame 10. The three force sensors 8 a, 8 b, 8 care arranged equidistantly in the circumferential direction. The pedal crankshaft 4 and the bearing 6 have a common axis of rotation. The force sensors 8 a, 8 b, 8 care arranged equidistantly in the circumferential direction about this axis of rotation. A first force sensor 8a is disposed at a 12 o'clock position as viewed in Fig. 1A. A second force sensor 8 bis disposed at a 4-o'clock position, and a third force sensor 8 cis disposed at an 8-o'clock position.The three force sensors 8 a, 8 b, 8 care designed as deformation sensors, here as strain gauges. The three force sensors 8 a, 8 b, 8 care designed to detect the respective radial force acting on the bearing 6 on the basis of a detected deformation of the bearing 6. If, for example, the bearing deforms in the region of the 12 o'clock position, that is to say in the region of the first force sensor 8 a, a radial force acting in the 12 o'clock position is detected by the pedal crankshaft 4 on the bearing 6 with the force sensor 8 a.The sensor arrangement 1 additionally has a data processing unit 12. The data processing unit 12 is part of the bicycle 2, wherein the bicycle 2 is shown in FIG. 2. The data processing unit 12 is designed to determine a total force applied to the crankshaft 4 by the driver of the vehicle 2 as a function of the detected radial forces. The total force, also referred to as driver force, represents a total force applied by the driver to the pedals, rotatably fastened to the pedal cranks. The data processing unit 12 is also used to determine a driving state of the driver. It is thus determined as a function of the detected radial forces whether the driver pedals while sitting or standing.The sensor arrangement 1 further comprises a means 12, 14 for determining an angular position of the pedal crankshaft 4. In the embodiment shown, a means 14 for determining the angular position of the pedal crankshaft 4 is an angle sensor 14. In a further embodiment, not shown here, the sensor arrangement 1 does not have an explicit angle sensor 14.Furthermore, the data processing unit 12 is designed as a further means 12 for determining the angular position of the pedal crankshaft 4. The data processing unit 12 is designed to determine the angular position of the pedal crankshaft 4 as a function of the detected radial forces. In this case, in one embodiment, a profile is taken into account. Depending on which radial forces are detected by the individual force sensors 8 a, 8 b, 8 c, for example also as a function of a detection time of individual radial forces, the angular position of the pedal crankshaft 4 is determined.The data processing unit 12 is designed to determine a driver torque on the crankshaft 4 as a function of the detected radial forces and as a function of the determined angular position of the crankshaft 4. Furthermore, the data processing unit 12 is designed to determine a driver's performance on the pedal crankshaft 4. In this case, the driver power is determined as a function of the determined driver torque and a carcass on the pedal crankshaft 4. The data processing unit 12 is designed to determine the carcass as a function of the angular position of the pedal crankshaft 4. Time-dependent values of the angular position are used to determine the carcass.Furthermore, FIG. 2 shows a drive train 16 for the vehicle 2. The drive train 16 has the sensor arrangement 1. Furthermore, the drive train 16 has a control device 18, which is formed separately from the data processing unit 12. In an alternative embodiment, not shown here, the control device is formed by the data processing unit 12. The control device 18 is designed to control a first element 20 and a second element 22 of the drive train 16 as a function of the detected radial forces. In this case, the control is carried out directly as a function of the detected radial forces. Furthermore, the control is carried out indirectly as a function of the detected radial forces, that is to say, for example, as a function of the determined driver torque.A drive motor 20 of the vehicle 2 is shown schematically as the first element 20 in FIG. 2, wherein the drive motor 20 is here an electric motor for driving the vehicle 2. Depending on the determined driver torque, the control of the drive motor 20 is performed by the controller 18. Thus, a multiple of the determined driver torque is used as a reference variable for regulating the drive motor 20.Furthermore, the second element 22 is designed as a transmission 22 of the vehicle 2. The transmission 22 has a plurality of transmission ratios. The transmission 22 further has an actuator for shifting between the transmission ratios. The transmission 22 is a continuously variable transmission in one embodiment. In an alternative embodiment, the transmission 22 is a discrete ratio transmission. If, for example, a driver torque is determined which is below a threshold value, the transmission ratio is increased by controlling the transmission by shifting with the actuator.In addition, the vehicle 2 according to the illustrated embodiment includes a user interface 24 for detecting a user input, which is attached to a handlebar of the bicycle. The user interface 24 is a touch screen display. The control device 18 is designed for controlling at least the second element 22 additionally as a function of detected user inputs. Information on a threshold value is acquired as user input. This threshold is then used to control the transmission 22. Thus, the user can specify from which threshold value of the driver torque a shift between transmission ratios is to be carried out. As a result, a shift between transmission ratios can be parameterized by the user or driver. This threshold value is then stored in a memory of the bicycle for later automatic shifting operations.The sensor arrangement 1 is communicatively connected to the control device 18, to the drive motor 20, to the actuator of the transmission 22 and to the user interface 24. In this case, a communication connection between these elements is at least partially wired in one embodiment. In an alternative embodiment, the communication link is at least partially wireless and is formed via Bluetooth.Reference numerals denote reference numerals1 Sensor arrangement 2 Vehicle 4 Pedal crankshaft 6 Bearing 8 a, 8 b, 8 c Force sensor 10 Frame 12 Data processing unit 14 Angle sensor 16 Drive train 18 Control device 20 Drive motor 22 Transmission 24 User interfaceReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 102012022447A1

[0002]

Claims

Sensor arrangement (1) for a muscle-powered vehicle (2) having a pedal crankshaft (4), a bearing (6) by means of which the pedal crankshaft (4) is rotatably mounted on a frame (10) of the vehicle (2), and at least three force sensors (8a, 8b, 8c) which are each designed to detect a radial force acting from the pedal crankshaft (4) on the bearing (6).Sensor arrangement (1) according to Claim 1, characterized in that the at least three force sensors (8a, 8b, 8c) are arranged on the bearing (6).Sensor arrangement (1) according to Claim 1 or 2, characterized in that the at least three force sensors (8a, 8b, 8c) are arranged equidistantly in the circumferential direction.Sensor arrangement (1) according to one of the preceding claims, characterized in that the at least three force sensors (8a, 8b, 8c) are designed as deformation sensors which are designed for detecting the respective radial force acting on the bearing (6) on the basis of a detected deformation of the bearing (6).Sensor arrangement (1) according to one of the preceding claims, characterized in that the sensor arrangement (1) has a data processing unit (12) which is designed to determine a total force applied by the driver of the vehicle (2) to the pedal crankshaft (4) as a function of the detected radial forces.Sensor arrangement (1) according to Claim 5, characterized in that the sensor arrangement (1) furthermore has a means (12; 14) for determining an angular position of the pedal crankshaft (4).Sensor arrangement (1) according to Claim 6, characterized in that the means (14) for determining the angular position of the pedal crankshaft (4) is an angle sensor (14).Sensor arrangement (1) according to either of Claims 6 and 7, characterized in that the means (12) for determining the angular position of the pedal crankshaft (4) is the data processing unit (12), the data processing unit (12) being designed for determining the angular position of the pedal crankshaft (4) on the basis of the detected radial forces.Sensor arrangement (1) according to one of Claims 6 to 8, characterized in that the data processing unit (12) is designed to determine a driver torque on the pedal crankshaft (4) as a function of the detected radial forces and as a function of the determined angular position of the pedal crankshaft (4).Drive train (16) for a muscle-powered vehicle (2) having a sensor arrangement (1) according to one of the preceding claims, wherein the drive train (16) has a control device (18), wherein the control device (18) is designed to control an element (20; 22) of the drive train (16) as a function of the detected radial forces.Drive train (16) according to Claim 10, characterized in that the element (20) is a drive motor (20) of the vehicle (2) which is designed to drive the vehicle (2).Drive train (16) according to Claim 10, characterized in that the element (22) is a transmission (22) of the vehicle (2) having a plurality of transmission ratios and an actuator for switching between the transmission ratios.Muscle-powered vehicle (2) having a sensor arrangement (1) according to one of Claims 1 to 9.Muscle-powered vehicle (2) according to Claim 13, characterized in that the vehicle (2) has at least one user interface (24) for detecting a user input, and in that the control device (18) is designed to control the element (20; 22) additionally on the basis of the detected user input.

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