The invention discloses a real-time high-precision detection method and system for a bolt pre-tightening force based on a piezoelectric ultrasonic wafer The piezoelectric ultrasonic chip is used as an ultrasonic excitation source to be attached to a bolt head, and a high-precision fitting relationship between an ultrasonic flight time difference and the bolt pre-tightening force is established byusing the change law of an ultrasonic single-wave time difference with the stress value; and real-time detection of the bolt pre-tightening force is achieved by using the mathematical relationship Compared with the prior method using the ultrasonic probe, the method provided by the invention eliminates the error caused by the uncertainty of the thickness of the coupling agent, and further improves the measurement accuracy by using the single-wave time difference Low-error-rate measurement of the bolt pre-tightening force is achieved at low cost and without influencing the structural performance

Real-time high-precision detection method and system for bolt pre-tightening force based on piezoelectric ultrasonic wafer

The invention relates to an angle-free vector force loading device, and belongs to the technical field of testing and calibration The angle-free vector force loading device comprises a pressure head (1), a one-way force sensor (2), a force sensor and hydraulic cylinder connecting block (3), a hydraulic cylinder (4), a sliding block (5), an arc-shaped plate (6), a rotating plate (7) and a fixed plate (8), wherein the rotating plate is mounted on the fixed plate; the arc-shaped plate is mounted on the rotating plate; the sliding block is mounted on the arc-shaped plate; the sliding block is connected with a standard vector force loading source consisting of the hydraulic cylinder, the connecting block, the one-way force sensor and the pressure head; the magnitude of a loading force is adjusted by manually controlling the hydraulic cylinder and reading a display value of the sensor in a matched manner, and directions of loading forces in the peripheral direction and the axial direction are adjusted by adjusting the rotating plate, the arc-shaped plate and the sliding block Compared with the prior art, the angle-free vector force loading device is good in stability, the magnitude of the loading force is accurately controlled by the high-precision one-way force sensor, angle-free vector force loading in the peripheral direction at an angle of 360 degrees and in the axial direction in an angle range between 0 degree and 20 degrees can be realized, and the angle-free vector force loading device is flexible and convenient to operate

Angle-free vector force loading device

A force detection apparatus includes a first member, a second member, a piezoelectric sensor device sandwiched by the first member and the second member and outputting electric charge according to an external force, and a conversion and output circuit converting an electric charge output from the piezoelectric sensor device into a voltage and outputting the voltage. When a detectable range of a component of the external force in a predetermined axis direction is a first range, the external force is detected within the first range. When the detectable range is a second range different from the first range, the external force is detected within the second range.

Force detection apparatus and robot

The invention belongs to the technical field of sensing measurement and control and provides a piezoelectric drilling dynamometer based on crossed non-equidistant arrangement of sensors. The piezoelectric drilling dynamometer is mainly composed of a work platform, piezoelectric sensors, a long support plate frame, a short support plate frame and a bottom plate, wherein the short support plate frame adopts a front-back symmetrical structure; the long support plate frame adopts a bilateral symmetrical structure; the work platform is cuboid; and the piezoelectric sensors are vertically arranged at a periphery and are mounted between the work platform and the support frames through pre-tightening bolts. According to the dynamometer, the conventional tension and compression effect is replaced by the whole shear effect of the sensors to measure an axial force of drilling; the dynamometer has high sensitivity, high precision and high inherent frequency and is suitable for dynamic measurementof deep hole drilling force of a hard and brittle material and small-range axial force, radial force and torque.

piezoelectric drilling dynamometer based on crossed non-equidistant arrangement of sensors

The invention belongs to the technical field of test, and provides a space vector force generating device with an adjustable angle. A circular-arc rail is mounted on a pedestal; a rear base is mountedon an arc-shaped rail; an arc-shaped plate is mounted on the rear base; a slide block is mounted on the arc-shaped plate; the upper surface of the slide block is connected with a hydraulic cylinder;a rear-end pull rod is connected with the hydraulic cylinder; one end of a joint is connected with the rear-end pull rod, and the other end of the joint is connected with a front-end pull rod; one endof a standard force sensor is connected to the front-end pull rod, and the other end of the standard force sensor is connected with a ball head connecting head; a ball head of the ball head connecting rod is matched with a ball bowl; the ball bowl is in threaded connection on a flange; the flange is connected on a supporting frame through a bolt; and the supporting frame is fixedly arranged on the pedestal through a bolt. The hydraulic cylinder is manually regulated to slide along the arc-shaped plate, and the rear base slides along the circular-arc guide rail, so that space vector force loading of any angle within a yaw angle being (-)30-30 degrees and a pitch angle being 0-30 degrees is realized, and the size of the vector force is regulated by reading a display value of a force sensor.

Space vector force generating device with adjustable angle

The invention discloses a piezoelectric small-range large-range ratio force-measuring device, which comprises piezoelectric crystal groups, fastening bolts, a pressure plate, sealing rings and a lead joint. The piezoelectric crystal groups serve as force-sensing elements and have the characteristics of high sensitivity, high stiffness and high natural frequency, and requirements of a high-precision test can be met. One X0 piezoelectric crystal group is arranged in the main direction, the other four Y0 crystal groups are arranged in two lateral directions, and thus vector forces in the main direction and the lateral directions are tested respectively. The fastening bolts are used for preloading piezoelectric crystal plates in the main direction and the lateral directions, the preloading force and a lateral force range can be adjusted, and the difficulty of testing a large range ratio of the main direction force and the lateral direction force can be solved. Due to the design of a two-way push-pull structure, influences on the test precision by outside temperature changes can be avoided. The test device has the advantages that the structure is simple, packaging is convenient, adjustment is convenient, and high-precision three-dimensional dynamic force test can be realized.

Piezoelectric small-range large-range ratio force-measuring device

The invention provides a calibration loading device for an adjustable pretightened piezoelectric dynamometer through a hydraulic pressure. The calibration loading device belongs to the fields of a sensor and measurement control of the sensor. The calibration loading device is composed of a loading cylinder sleeve, a loading plunger, a pretightening spring, a pretightening adjusting sleeve, a loading rod and a dynamic sealing ring. The calibration loading device can perform calibrated loading on a condition that a loading force source is far from the piezoelectric dynamometer or the piezoelectric dynamometer is arranged in a sealed chamber. The pretightening adjusting sleeve can adjust a pretightening force of the loading plunger, thereby reducing retardation of the loading device in performing return stroke calibration on the piezoelectric dynamometer, furthermore ensuring a fact that the loading plunger can return to an original position after pressure discharging is finished, and improving testing precision to the piezoelectric dynamometer.

Calibration loading device for adjustable pretightened piezoelectric dynamometer through hydraulic pressure

The invention discloses a self-centering vector force loading device, and belongs to the field of mechanics. The device comprises a loading rod, a sealing ring, a substrate, a loading apparatus, and a self-centering apparatus. Through the changing of the positions of a rotating flange and an unbalance loading flange in the loading apparatus, the device achieves the adjustment of a three-dimensional vector force in different loading directions. The device achieves the self-centering force loading through a spherical positioning block and a conical positioning block in the self-centering apparatus, and effectively reduces loss caused by axis bending when the three-dimensional force is loaded. The substrate guarantees the flatness of the front and rear surfaces, prevents a force unbalance loading angle from being generated, and avoids the impact on the direction of the vector. The device achieves the loading of the vector force for the loading rod through hydraulic pressure, and a loading process is stable and high in precision. The device is simple in structure, is high in rigidity, is convenient for the flexible adjustment of the direction of the loading force, and achieves the loading of a big high-precision three-dimensional vector force.

Self-centering vector force loading device

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Piezoelectric small-range large-range ratio force-measuring device

Calibration loading device for adjustable pretightened piezoelectric dynamometer through hydraulic pressure

Self-centering vector force loading device